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Biochemical  Studies  of 
Mercaptan 


RECAP 


D155LRTATION 

SUBMITTED  IN  PARTIAL  FULFILMENT  OF  THE  REQUIRE- 
MENTS FOR  THE  DEGREE  OF  DOCTOR  OF   PHILOSO- 
PHY IN  THE  FACULTY  OF  PURE  SCIENCE 
OF  COLUMBIA  UNIVERSITY 


BY 

FRLDLRIC  GR05VLN0R  GOODRIDGL,  B.A.,  M.D. 

NEW  YORK  CITY 
1915 


Easton,  Pa.: 

EscHENBACH  Printing  Co. 

1915 


ajt3Ll2Jf^ 


jSl£JL 


tntl)eCilpoflrtti||0rk 

College  of  ^^pfiitianst  an&  ^urgeonsf 

^ibrarp 


Digitized  by  tine  Internet  Arciiive 

in  2010  with  funding  from 
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Biochemical  Studies  of 
Mercaptan 


DISSERTATION 

SUBMITTED  IN  PARTIAL   FULFILMENT   OF   THE   REQUIRE- 
MENTS FOR  THE  DEGREE  OF  DOCTOR  OF   PHILOSO- 
PHY IN  THE  FACULTY  OF  PURE  SCIENCE 
OF  COLUMBIA   UNIVERSITY 


BY 

FRLDLRIC  GR05VLN0R  GOODRIDGL,  B.A.,  M.D. 

NEW  YORK  CITY 
1915 


Easton,  Pa.: 
EscHENBACH  Printing  Co. 
1915 


OP'/ 


TO  MY  WIFE. 


ACKNOWLEDGMENT. 
My  thanks  are  due  to  Professor  William  J.   Gies,  without 
whose  stimulating  personality  this  work  could  not  have  been 
accomplished,   and   to   Professor  Charles  C.  Lieb  for  his  un- 
varying courtesy  and  valuable  suggestions.  F.  G.  G. 

Laboratory  of  Biological  Chemistry, 
College  op  Physicians  and  Surgeons. 
Columbia  University,  New  York, 
February  5,  1915. 


TABLE  OF  CONTENTS. 

PAGE. 

Dedication 3 

Acknowledgment 4 

Chapter      I.        Introduction 7 

Formation  of  mercaptan  in  the  body 11 

Detection  and  determination  of  mercaptan 13 

Occurrence  of  mercaptan 15 

Physiology,  Pharmacology  and   Pathology  of  Mer- 
captan    19 

Chapter   II.        Comparison  of  the  various  methods  for  the  detec- 
tion of  mercaptan 22 

Mercaptan  and  volatile  sulfides  in  normal  human 

urine 28 

Mercaptan  and  volatile  sulfides  in  dog  urine 29 

Volatile  sulfides  and  mercaptan  in  human  feces 30 

Volatile  sulfides  and  mercaptan  in  the  urine  of  a  dog 

fed  on  a  rich  protein  diet 30 

Volatile  sulfides  and  mercaptan  in  the  urine  of  a  dog 

fed  on  a  poor  protein  diet 31 

Isatin-sulf uric  acid  method 31 

Complicating  effects  of  preservatives 32 

lodometric  method 32 

Volatile  sulfides  and  mercaptan  in  the  urine  of  a  dog 

fed  mercaptan 33 

Bacterial  formation  of  mercaptan 33 

The  occurrence  of  mercaptan  in  disease 34 

Depressive  mania 35 

Exalted  mania 35 

Toxemia  of  pregnancy — mild  cases 35 

Fatal  eclampsia 36 

Chronic  interstitial  nephritis 36 

Chronic  parenchymatous  nephritis 36 

Lobar  pneumonia 37 

Sulfur  partitions  in  lobar  pneumonia 38 

Malignant  disease 38 

•                     Pyelitis  and  cystitis 39 

Cholelithiasis 39 

Diabetes '. 40 

Conclusions 40 

Mercaptan  in  the  gastric  contents  of  dogs   in  which 

the  pylorus  had  been  tied  off 40 

Effect  of  mercaptan  on  enzymes,  bacteria  and  fungi.  41 

Chapter  III,       Pharmacology  of  mercaptan 43 

Action  of  mercaptan  on  frogs 44 


Action  of  mercaptan  on  guinea  pigs 46 

Comparison   of    the   toxic  effects    of   methyl-, 
ethyl-,  propyl-,  and   isobutyl-mercaptans  on 

guinea  pigs 51 

Action  of  mercaptan  on  dogs 53 

Effect  of  mercaptan  on  man 54 

Effect  on  seedlings .' 55 

Effect  of  mercaptan  on  the  blood  pigments 55 

General  conclusions 56 

Bibliography 58 

Biographical 61 

PubUcations 62 


CHAPTER  I. 
Introduction. 

In  1833,  in  the  forty-first  volume  of  Schweigger-Seidel's 
Jahrbuch,  Zeise  reported  the  discovery  of  a  new  class  of  sulfur 
compounds  to  which  he  gave  the  name  mercaptan,  because  of 
their  great  affinity  for  mercury — corpus  mercurio  aptum.^  In 
the  next  year  an  abstract  of  the  paper  by  Zeise  appeared  in 
the  Annalen,  with  the  criticism  and  praise  of  Liebig.  Since 
then  articles  on  the  pure  chemistry  of  the  mercaptans  have 
appeared  at  rather  rare  intervals  in  the  various  chemical 
journals.  Biochemical  studies  of  the  thio-alcohols  have  also 
been  undertaken,  but  the  research  in  this  field  has  been  des- 
ultory and  casual.  Bacteriologists  have  noticed  the  produc- 
tion of  mercaptan  by  anaerobic  micro-organisms,  and  students 
of  hygiene  have  superficially  examined  its  occurrence  in  corrupt 
atmospheres,  but  the  toxic  effects  of  this  substance  have  not 
been  carefully  investigated. 

In  his  original  communication,  Zeise  reported  the  prepara- 
tion of  several  sulfur-containing  compounds  which  on  further 
investigation  proved  to  be  definitely  different  from  one  another. 
A  neutral  member  of  these  he  named  thialol,  and  another, 
which  possesses  many  of  the  peculiarities  of  sulfo-cyanic  acid, 
he  named  mercaptan. 

Pure  ethyl-mercaptan  is  a  colorless,  ether-soluble  substance, 
slightly  decomposed  by  light,  has  a  specific  gravity  at  15°  C. 
of  0.842,  and  a  boiling  point,  at  28  millimeters  mercury,  of 
61-63°  C.  It  volatilizes  at — 22  °C.,  and  is  very  inflammable. 
It  is  slightly  soluble  in  water,  but  very  soluble  in  alcohol  and 
ether.  The  aqueous  or  alcoholic  solutions  turn  platinum 
chloride  pale  yellow,  sUver  nitrate  and  mercuric  oxide  white, 
copper  and  lead  acetate  pale  yellow,  and  in  the  presence  of  an 
excess  of  mercaptan  no  more  metal  will  remain  in  the  solution. 
In  its  action  on  the  oxides,  mercaptan  shows  a  noticeable 
variability.     On  calcium  oxide  it  has  no  effect,  on  copper  oxide 

•  Zeise:  Liebig's  Annalen,  1834,  xi,  p.  10. 


8 

a  slow  action,  on  lead  oxide  an  abundant  precipitate  is  formed, 
while  with  gold  and  silver  oxides,  especially  when  diluted  with 
alcohol,  it  causes  a  marked  rise  in  temperature.  With  calcium 
hydroxide  in  either  aqueous  or  alcoholic  solution  it  has  no 
reaction. 

On  boiling  with  potassium  hydroxide  merciuric  mercaptide 
is  not  changed.  Oxidizing  agents  do  not  affect  it,  except  nitric 
acid,  by  which  it  is  violently  decomposed  with  the  formation 
of  an  oily  product.  By  concentrated  hydrochloric  acid  it  is 
dissolved  into  a  clear  fluid  which  is  turned  pale  yellow  by  the 
addition  of  a  potassium  salt.  Aqua  regia  also  decomposes  it 
with  the  formation  of  sulfur  chloride  and  an  unusually  pungent 
steam.  Melted  mercuric  mercaptide  is  decomposed  by  equal 
parts  of  metallic  lead  and  lead  mercaptide,  and  lead  amalgam 
is  formed. 

It  has  been  attempted  unsuccessfully  to  join  the  radical  mer- 
captan  to  sulfur  by  fusion.  When  mixed  with  mercuric  chloride 
they  fuse  together  easily,  and  on  heating  at  a  high  temperature 
a  colorless,  thin,  ethereal  fluid  is  formed  which  differs  from  mer- 
captan.  This  contains  chloride  from  which  it  is  separated  by 
decomposition  with  metallic  mercury,  leaving  a  metallic  mass 
as  a  residue  which  may  be  drawn  into  long  ribbons. 

Of  the  lower  mercaptans,  the  methyl  compound,  CH3SH, 
has  received  the  most  attention  on  account  of  its  frequent 
presence  in  the  animal  body.  Many  of  its  characteristics  are 
possessed  in  common  with  the  other  lower  thio-alcohols,  which 
may  be  enumerated  as  follows:  Methyl-mercaptan  is  a  fluid 
with  a  most  unpleasant  odor,  and  a  boiling  point  at  about  6  °  C, 
and  a  freezing  point  at  — 130.5  °  C.  It  is  barely  soluble  in  water 
(5  parts  in  1000),  easily  soluble  in  alcohol  and  ether,  and  in 
aqueous  alkaline  solutions  with  the  formation  of  relatively 
stable  alkaline  salts.  By  means  of  mild  oxidizing  substances, 
as  iodine,  methyl-mercaptan  is  changed  to  methyl  sulfide: 

2CH3SH   +   I2    =    (CH3)2S2   +    2HI 

It  enters  into  combination  easily  with  the  heavy  metals  to 
form  mercaptides.     The  mercuric  compound,    (CH3S)2Hg,   is 


best  obtained  by  passing  methyl-mercaptan  through  a  3  per 
cent,  solution  of  mercuric  cyanide.  The  mercuric  mercaptide 
thus  formed  is  a  white  salt  which  turns  gray  on  exposure  to  the 
air.  It  consists  of  ill-defined,  four-sided  prisms  which  melt  at 
175°  C,  and  are  insoluble  in  water,  alcohol  and  ether.  With 
corrosive  sublimate,  a  double  union  is  formed,  (CH3S)2Hg.HgCl2, 
from  which  mercuric  mercaptide,  (CH3S)2Hg,  may  be  obtained . 
The  normal  mercuric  mercaptide  goes  over  into  the  double 
salt  on  the  addition  of  cold  concentrated  hydrochloric  acid. 
A  soluble  double  salt  is  formed  by  the  digestion  of  the  insoluble 
normal  mercaptide  with  a  strong  mercuric  acetate  solution. 
By  dry  heating,  mercuric  mercaptide  is  decomposed  into  the 
metal  and  the  disulfide: 

CH3S 

yUg  =  CH3S.SCH3  +  Hg 

CH3S 
The  lead  compound  is  most  easily  prepared  by  passing  the  mer- 
captan  gas  into  a  3  per  cent,  solution  of  lead  acetate.  This 
forms  a  yellow  precipitate  consisting  of  plates  and  prisms 
which  turn  brown  on  exposure  to  the  air.  Lead  mercaptide 
is  insoluble  in  water,  alcohol  and  ether  and  fairly  soluble  in 
concentrated  solutions  of  lead  salts.  Hydrogen  sulfide  changes 
the  yellow  crystals  to  brown  on  account  of  the  formation  of 
lead  sulfide;  the  color  can  be  restored,  however,  by  washing 
with  alcohol.  On  heating  the  dry  lead  mercaptide  it  is  changed 
to  lead  sulfide  and  methyl  sulfide: 

(CH3S)2Pb  =  (CH3)2S  +  PbS 
The  mercaptides  formed  with  the  salts  of  the  precious  metals 
are  generally  more  soluble  than  the  mercuric  or  plumbic  com- 
pounds.    The  reactions  are  very  delicate  and  take  place  easily 
in  the  presence  of  free  mineral  acids. 

History. 
This  study  of  the  biochemistry  of  the  mercaptans  was  un- 
dertaken as  one  of  a  series  of  investigations  of  the  relationship 
between  the  unoxidized  sulfur  products  and  certain  intoxi- 
cations. 


lO 


The  further  decomposition  of  the  protein  molecule  by  means 
of  the  anaerobic  bacteria  existing  normally  in  the  intestinal 
tract,  as  B.  lactis  aerogenes,  B.  bifidus,  and  the  B.  coli  communis, 
gives  rise  to  many  substances  of  both  the  aromatic  and  aliphatic 
series.  If  these  substances  enter  the  blood  in  the  process  of 
absorption  they  pass  through  the  portal  vein  into  the  liver  and 
are  there  conjugated  with  acetic,  sulfuric,  glycuronic  or  tauro- 
cholic  acids,  etc.,  synthesized,  oxidized  or  reduced,  etc.,  and 
pass  into  the  general  circulation  in  a  changed  condition  to  be 
eliminated  in  the  breath,  sweat,  feces  or  urine.  Many  of  these 
substances  possess  a  certain  amount  of  toxicity,  but  under  normal 
conditions  they  are  so  changed  as  to  be  relatively  harmless  to 
the  organism.  In  disease,  however,  when  the  normal  defenses 
of  the  body  are  temporarily  out  of  gear  or  permanently  broken 
down,  the  metabolic  processes  are  so  changed  that  some  of 
these  poisons  may  reach  the  tissues  and  become  a  menace. 

The  phenol  and  indol  groups  of  the  aromatic  products  of 
putrefaction  have  been  assiduously  studied  and  the  presence 
of  indican  has  been  accepted  as  a  measure  of  the  extent  of  the 
intestinal  putrefaction  present.  But  the  toxicity  of  these  aro- 
matic products  will  result  in  the  appearance  of  such  symptoms 
as  discomfort  and  headache,  which  are  rather  mild.  There 
are  certain  diseases,  however,  that  suggest  a  cause  associated 
with  faulty  intestinal  processes,  the  symptoms  of  which  are 
convulsions  due  to  an  irritation  of  the  cerebral  cortex,  hemolysis 
and  destruction  of  tissue,  which  must  be  produced  by  a  far  more 
violent  poison  or  poisons.  These  would  seem  to  be  formed  in 
small  amounts,  rapidly  diffused  and  ftdminating  in  effect, 
as  in  gastric  tetany,  certain  idiopathic  epilepsies,  the  con- 
vulsive stage  of  toxemia  of  pregnancy  and  the  uremic  mani- 
festations of  nephritis;  or  of  slow  formation  and  cumulative 
action  as  in  hepatic  cirrhosis,  arteriosclerosis,  pernicious 
anemia,  the  early  stages  of  the  toxemia  of  pregnancy  and  chronic 
nephritis.  The  occurrence  of  mercaptan  in  these  diseases  will 
be  dilated  upon  in  a  succeeding  chapter. 

It  is  conceivable  that  some  of  the  toxic  action  may  be  caused 
by  the  close  contact  of  the  poisonous  material  and  the  terminal 


II 

nerve  endings  in  the  mucosa  of  the  intestine  (plexuses  of  Auer- 
bach  and  Meissner),  a  semi-permeable  membrane  alone  inter- 
vening, but  if  the  poison  can  pass  through  the  membrane  it 
must  get  into  the  blood  stream;  and  if  it  reaches  the  blood 
stream,  it  will,  in  aU  likelihood,  be  ehminated  in  the  mine,  un- 
less a  decomposition  or  a  resynthesis  and  a  consequent  entire 
change  of  chemical  and  physical  condition  takes  place. 

The  Formation  of  Mercaptan  in  the  Body. — The  mercaptan 
group  in  the  various  secretory  and  excretory  organs  of  the  body 
is  probably  derived  from  the  sulfur-containing  protein  molecule. 
The  exact  stages  of  the  protein  decomposition,  however,  are 
unknown,  and  the  various  means  whereby  mercaptan  may  be 
formed  have  as  yet  no  experimental  basis  or  very  weak  proofs. 

A  theory  advanced  by  Abderhalden^  and  others  is  that  the 
breaking  down  of  cystin,  which  is  a  decomposition  product 
of  certain  proteins,  may  give  rise  to  this  thio-alcohol  group. 
Cystin  is  di-thio-diamino-dilactic  acid: 

CH2— S— S— CH2 
H2N-CH  CH-NH2 

COOH       COOH 

It  occurs  in  some  calculi  and  in  certain  urinary  sediments, 
and  is  obtained  by  hydrolysis,  with  weak  hydrochloric  acid,  of 
horn  scrapings,  human  hair,  lamb's  wool,  etc.  By  reduction 
with  tin  and  hydrochloric  acid,  cystin  yields  cystein,  alpha- 
amino-beta-thio-lactic  acid : 

CH2SH-CHNH2-COOH 

This  is  a  very  unstable  substance.  In  the  air  it  rapidly  oxidizes 
to  cystin.  Ferric  chloride  also  oxidizes  it  with  the  production 
of  indigo-blue  color.  If  cystin  is  decarboxylated,  an  amino 
thio-alcohol  is  formed,  which  may  yield  ethyl-mercaptan : 

'  C.  A.  Hilger:  Liebig's  Annalen,  clxxi,  p.  208;  Karplus:  Virchow's 
Archiv.,  1893,  cxxxi,  p.  210;  Konig:  Zeit.  f.physiol.Chemie,  iSQi.xvi,  p.  525- 


12 


CHaSH 
CHNH2 


CH2SH  CH2SH 

CH2NH2  CH3 


COOH 

Of  course  with  lower  or  higher  homologues  of  cystin,  lower 
or  higher  homologues  of  mercaptan  might  be  produced. 

A  large  part  of  the  breaking  down  of  the  protein  molecule 
is  accompHshed  by  the  micro-organisms  of  the  intestinal  tract, 
and  it  is  quite  possible  by  their  action  that  the  mercaptan  group 
is  directly  split  ofif.  It  has  been  shown  that  the  eating  of  certain 
vegetables  causes  a  marked  output  of  methyl-mercaptan  in  the 
lurine,  but  it  has  not  been  demonstrated  that  as  a  prehminary 
stage  to  this  change  cystin  was  formed. 

It  has  been  suggested  that  there  may  be  a  direct  union  of 
methane  and  hydrogen  sulfide  in  the  intestinal  tract.  This 
might  be  accomplished  by  the  intervention  of  enzymes  or  bac- 
teria. In  vitro,  however,  the  paraffins  do  not  unite  directly 
with  hydrogen  sulfide,  but  the  body  has  many  methods  at  its 
disposal  which  the  laboratory  worker  lacks. 

CH4  +  H2S  =  CH3SH  +  H2 

In  the  taurin  arrangement  there  is  another  possible  deriva- 
tion of  mercaptan.  Taurin  occurs  in  the  bile  as  taurocholic 
acid,  which  is  decomposed  by  hydrochloric  acid  to  tamin  and 
cholic  acid. 

C26H45NO7S     =     C2H7NSO3     +     C24H40O5     ■ 
(taurocholic  acid)  (taurin)  (choUc  acid) 

Taurin  contains  the  amino  and  the  sulfonic  acid  groups,  and  it  is, 
therefore,  both  a  base  and  an  acid.  By  the  reduction  of  a  sul- 
fonic acid  there  may  be  produced,  first  sulfinic  acid  and  then  a 
mercaptan : 

CH2NH2  CH2NH2  CH2NH2  CH3 

CH2SO2OH        CH2SOOH  CH2SH  CH2SH 

(taurin — asul-    (sulfinic  acid)     (amino  (mercaptan) 

fonic  acid)  mercaptan) 


13 

Detection  and  Determination  of  Mercaptan. — Neither  quali- 
tative nor  quantitative  methods  for  the  determination  of  or- 
ganic compounds  are  as  dehcate  or  as  accm-ate,  as  a  rule,  as 
the  methods  followed  in  the  analysis  of  inorganic  substances. 
The  possible  isomeres,  the  facility  with  which  organic  compounds 
oxidize,  reduce  and  polymerize  are  among  the  reasons  for  the 
lack  of  accuracy  in  many  phases  of  organic  analysis.  Even 
in  the  preparation  of  compounds  from  pure  material,  a  yield 
of  about  50  per  cent,  is  in  certain  cases  considered  satisfactory. 
This  is  especially  true  of  the  mercaptans  on  account  of  their 
great  volatility.  They  have,  however,  an  advantage  over  other 
substances  in  that  their  extremely  unpleasant  odor  facilitates 
their  detection  in  most  minute  traces.  Fischer  and  Penzoldt^ 
waved  a  cloth  wet  with  different  amounts  of  ethyl-mercaptan 
about  a  lecture  hall  and  found  that  the  olfactories  of  the  stu- 
dents were  able  to  detect  1/460,000,000  of  a  milligram  of  the 
substance.  This  will  give  some  idea  of  the  extremely  powerful 
odor  of  the  material,  but  of  its  disagreeable  character  only  its 
investigators  can  have  a  proper  conception.  This  odor,  how- 
ever, serves  as  a  method  for  the  qualitative  determination  of 
the  presence  of  the  lower  mercaptans,  that  is  more  delicate 
than  the  spectral  analysis  of  sodium  by  which  only  1/1,400,000 
gram  of  that  substance  can  be  detected. 

An  alkaline  solution  of  sodium  nitroprusside^  colors  all  mer- 
captans violet,  a  color  which  disappears  on  acidulating  and  re- 
appears after  the  addition  of  an  alkali.  The  presence  of  hy- 
drogen sulfide  does  not  interfere  with  the  reaction  if  an  alkaline 
lead  acetate  solution  is  added  to  the  nitroprusside  solution, 
so  that  the  hydrogen  sulfide  will  unite  with  the  lead  to  form 
plumbic  sulfide. 

The  most  serviceable  laboratory  test  for  the  presence  of 
mercaptan  is  that  dependent  Upon  the  change  of  the  color  of 
isatin  in  concentrated  sulfuric  acid.^     Isatin  is  formed  by  the 

'  Fischer  and  Penzoldt:  Maly's  Jahresbericht  der  Thierchem.,   1886, 
P-  324- 

^  Denig^s:  Compt.  rend.,  1889,  cix, . 

'  C.  A.  Ilerter:  Jour.  Biol.  Chcm.,  1906,  i.  p.  421.     See   Denigds,  1.  c. 


14 


complete  oxidation  of  indol  and  consists  of  shining  red  plates. 
The  following  graphic  formulae  will  show  the  stages  of 
change  from  indole  to  isatin: 

H  H 


"V^V^ 


c=o 


c 

H 


N 
H 


isatin 


The  addition  of  a  very  small  amount  of  this  substance  to 
concentrated  sulfuric  acid  forms  a  yellow-red  solution.  In 
the  presence  of  mercaptan  this  color  is  changed  at  once  to 
a  deep  green,  the  color  resembling  that  of  bile.  Herter 
found  that  25  milligrams  of  mercaptan  changed  50  cc.  of 


15 

the  reddish  isatin  solution  to  green  in  ten  minutes.  Other 
sulfur  compounds  and  alcohol,  acetone,  etc.,  do  not  eflFect 
the  reaction. 

For  the  quantitative  determination  of  mercaptan  both 
colorimetric  and  gravimetric  methods  have  been  used. 

Niemann^  in  his  study  of  the  separation  of  carbon  di- 
oxide, mercaptan  and  hydrogen  sulfide,  from  various  animal 
and  vegetable  food  stufiFs,  employed  the  following  procedure : 
500  grams  of  the  substance  to  be  examined  are  macerated 
and  placed  in  a  three-liter  flask  to  which  are  added  1000 
cc.  of  distilled  water.  The  contents  are  then  distilled 
through  a  Liebig  condenser  and  the  vapor  collected  in  a 
flask  containing  a  3  per  cent,  solution  of  mercuric  cyanide. 
The  white  precipitate  is  separated  on  a  hard  filter  paper, 
and  washed  into  a  flask  containing  dilute  acetic  acid. 
Upon  the  addition  of  lead  acetate  a  lemon-yellow  precipi- 
tate of  lead  mercaptide  forms  which  is  filtered  off,  dried 
at  45°  C.  and  weighed.  The  details  of  this  method  were 
later  modified  so  that  the  precipitate  is  placed  in  a  flask 
about  half  filled  with  10  per  cent,  acetic  acid  to  which 
200  cc.  of  3  per  cent,  lead  acetate  solution  is  added  through 
a  dropping  funnel  and  25  cc.  of  5  per  cent,  hydrochloric 
acid.  If  the  lead  mercaptide  fails  to  separate,  the  solution 
is  heated  slowly. 

Only  one  titrimetric  method  has  been  described.  After 
precipitation  with  lead  acetate,  25  cc.  of  5  per  cent,  hy- 
drochloric acid  are  added.  The  mercaptan  gas  formed  is 
collected  by  an  outgoing  tube  into  a  known  amount  of 
decinormal  iodine  solution.  In  order  to  make  certain  that 
the  gas  has  completely  passed  into  the  iodine  solution  the 
flask  containing  the  lead  acetate  and  the  hydrochloric  acid 
is  gently  heated,  and  the  excess  of  iodine  solution  is  de- 
termined by  titrating  back  with  standardized  sodium  thio- 
sulfate  solution. 

Occurrence  of  Mercaptan. — The  mercaptans  occur  quite 
frequently  in  the  animal  and  vegetable  kingdoms.  In 
'  Niemann:  Arch.  f.  Hyg.,  1893,  xix,  p.  117. 


i6 

human  beings  methyl-mercaptan  is  found  normally  in  the 
urine  after  partaking  of  asparagus  \  cauliflower  and  cab- 
bage, ^  and  pathologically  in  certain  diseases,  as  in  pneu- 
monia^. It  is  also  produced  in  the  ileum  and  ascending 
colon  by  the  action  of  certain  of  the  anaerobic  micro- 
organisms on  protein  food  stuffs.  L.  Nencki^  found  mer- 
captan  constantly  present  in  the  gases  formed  from  the  de- 
composition of  normal  feces.  Herter^,  however,  failed  to 
find  it  in  the  feces,  but  believed  it  to  be  formed  higher  up 
in  the  intestines  and  to  be  absorbed.  He  also  concluded 
that  its  presence  in  Nencki's  determination  was  due  to  the 
further  decomposition  of  the  feces  outside  of  the  body,  a 
possibility  which  Herter  avoided  by  using  fresh  specimens. 

Normal  butyl-mercaptan  is  found  in  the  anal  secretion 
of  all  the  members  of  the  skunk  family  together  with  butyl 
sulfide  and  traces  of  methyl-mercaptan.^  In  a  report  of 
his  travels  in  northern  Texas,  Loew  says'^:  "I  had  an 
opportunity  of  studying  the  excretion  of  Mephitis  Texana, 
but  the  objections  of  my  travelling  companions  hindered 
me."  He  describes  the  oil  as  having  a  very  vile  garlicky 
odor.  Later  Swarts^  studied  the  composition  of  this  oil 
and  separated  two  fractions,  one  boiling  at  from  105°  to 
110°  C,  and  the  other  at  from  190°  to  200°  C.  The  oil 
was  very  rich  in  sulfur  and  contained  much  of  several 
mercaptans,  to  which  the  foul  odor  was  due.  Aldrich  also 
found  iso-amyl-mercaptan  present  in  the  anal  secretion  of 
the  common  skunk. 

Upon    distillation    with    steam    certain    vegetables    yield 

1  M.  Nencki:  Archiv.  f.  exper.  Path.  u.  Pharmac,  1891,  xxviii,  p.  206. 

2  M.  Rubner:  Arch.  f.  Hyg.,  1893,  xix,  p.  136. 

^  J.  P.  Karplus:  Virchow's  Archiv.,  1893,  cxxxi,  p.  210. 

*  L.  Nencki:  Sitzungsber.  d.  Mathem.  Naturw.  Akad.  Wien,  1889, 
xcvii,  part  3,  p.  437. 

^  C.  A.  Herter:  Jour.  Biol.  Chem.,  1905,  i,  p.  421. 

8  Aldrich:  Jour.  Exp.  Med.,  1897,  i,  p.  323;  Amer.  Jour.  Physiol.,  1901, 
V,  p.  457- 

''  O.  Loew:  Aerztl.  Intelligenzbl.  von  Mtinchen,  May,  1879. 

*Swarts:  Jahresber.  f.  Chem.,  1883. 


17 

slight  amounts    of    methyl-mercaptan.     The  results  of  Nie- 
mann's^ researches  show  these  to  be: 

Weight.  Mercaptan. 

Gm.  Gm. 

Brassica  Oleracea  Capitata  Alba.  .      500  0.034 

Botr3dis 800  0.168 

"  "  Gummifera 800  0.064 

"  "  Cautoropa 500  trace 

Asparagus none 

Lettuce 

Spinach 

Potatoes 

Semmler-  also  found  slight  quantities  of  vinyl-mercaptan 
in  Allium  ursinum. 

Several  bacteriologists  have  found  that  upon  growing 
certain  micro-organisms  on  special  culture  media  methyl- 
mercaptan  is  produced  in  quite  appreciable  quantities.  In 
1899,  Nencki  and  Sieber^  studied  the  gases  produced  by 
the  growth  of  bacteria  on  egg  white.  The  B.  liquefaciens 
magnus  grown  under  anaerobic  conditions  on  egg  white  for 
a  period  of  13  days  produced  gases  which  were  analyzed. 
These  were  found  to  be  composed  of  97.1  per  cent,  by  volume 
of  gases  absorbable  by  potassium  hydroxide  and  2.63  per  cent, 
hydrogen .  Upon  dissolving  the  alkali  in  water  and  acidulating 
with  acetic  acid  a  very  distinct  odor  of  mercaptan  was  obtained. 
The  addition  of  corrosive  sublimate  or  silver  nitrate  resulted 
in  the  production  of  a  white  precipitate;  while  lead  acetate 
and  copper  sulfate  gave  yellowish  brown  precipitates. 
A  year  previous  to  this  report  Luderitz^  noticed  that,  in 
growing  the  B.  liquefaciens  magnus,  a  very  vile  odor  re- 
sembling that  of  decaying  cheese  and  onions  was  produced. 

Karplus^  found  that  certain  bacteria  decomposed  the 
sulfur  fraction   in   the  urine   and   caused   the  formation   of 

'  F.  Niemann:  Arch.  f.  Hyg.,  1893,  xix,  p.  117. 

*  F.  W.  Semmler:  Liebig's  Annalen,  1887,  ccxli,  p.  109. 

'  M.   Nencki  and  N.   Sieber:  Sitsungsber.   d.   Mathem.   Naturwiss. 
Akad.  Wien,  1889,  xcviii,  part  2b,  p.  417. 

♦  Luderitz:  Zeit.  f.  Hyg.,  1888,  v,  p.  147. 

'  Karplus:  Virchow's  Archiv.,  1893,  cxxxi,  p.  210. 


i8 

small  amounts  of  methyl-mercaptan  and  hydrogen  sulfide. 
Upon  growing  the  B.  Uquefaciens  magnus  under  anaerobic 
conditions,  SeHtienny^  also  found  that  methyl-mercaptan 
was  formed.  Rubner^  reported  the  production  of  the  lower 
thio-alcohol  by  the  growth  of  B.  proteus  vulgaris  in  bouillon 
and  gelatine  cultures,  and  also  by  B.  tetanus  when  grown 
under  anaerobic  conditions.  Metchnikoff^  failed  to  obtain 
any  mercaptan  from  growing  cholera  bacilli  on  egg  white 
culture  media.  Buijwid^  on  the  contrary,  was  quite  suc- 
cessful. 

Other  observers  have  found  that  methyl-mercaptan  is 
one  of  the  products  of  the  metabolism  of  Penicillium 
glaucum  and  Saccharomyces  cerevissiae.  Mathieu^  states 
that  ethyl -mercaptan  may  be  formed  in  any  urine  which 
contains  sulfur.  In  the  presence  of  yeast  in  urine  there  is 
first  the  production  of  hydrogen  sulfide  and  then  of  the 
ethylthio-alcohol.  This  takes  place  especially  in  the  early 
part  of  the  fermentation,  when  sugar  is  present  in  com- 
paratively large  quantities. 

According  to  Herter  the  most  active  mercaptan  pro- 
ducer among  the  anaerobes  is  B.  putrificus.  He  says: 
"In  every  instance  in  which  B.  putrificus  is  present  in 
bouillon  flasks  prepared  by  growing  the  mixed  fecal  flora 
from  cases  of  intestinal  putrefaction  there  is  found  also 
methyl-mercaptan.  This  observation  corresponds  to  the 
fact  that  the  B.  putrificus  in  pure  culture  in  peptone- 
bouillon  is  capable  of  making  mercaptan.  It  has  not  al- 
ways been  possible  to  grow  B.  putrificus  from  cases  in 
which  a  methyl-mercaptan  reaction  was  obtained  and  for 
this  reason,  and  others,  I  believe  that  methyl-mercaptan 
may  be  produced  by  other  intestinal  organisms  than  the 
B.  putrificus.      Nevertheless,  in  my  experience  the  strongest 

1  Selitienny:  Cited  after  Abderhalden's  Biochem.Handlexicon. 

2  Rubner:  Hyg.  Rundschau,  1893,  cxi,  p.  525. 

3  E.  Metchnikoff :  Cited  after  Abderhalden's  Biochem.  Handlexicon. 
*  Buijwid:  Centralblatt  f.  BacterioL,  1893,  No.  4. 

^Mathieu:  Bull,  de  I'Associat.  des   Chim.  de  Sucre  et  Distil.,  1911, 
xxviii,  p.  971. 


19 

methyl-mercaptan  reactions  have  been  obtained  from  those 
cases  in  which  B.  putrificiis  was  present  and  this  bacillus 
makes  more  mercaptan  when  grown  in  peptone-bouillon 
than  any  other  anaerobe  with  which  we  have  experimented. 
Although  not  a  normal  inhabitant,  B.  putrificus  owing  to 
its  frequent  presence  in  certain  foods  is  usually  found  in 
the  digestive  tract.  B.  aerogenes  capstdatus  is  also  a  mer- 
captan  producer." 

Physiology,  Pharmacology  and  Pathology  of  Mercaptan. — 
The  principal  work  on  the  physiological  action  of  mer- 
captan has  been  done  by  Rekowski^  in  Russia  and  Herter  in 
this  country.  The  former,  working  in  Nencki's  laboratory, 
experimented  on  the  action  of  the  gas  upon  white  mice  and 
rabbits  and  the  effects  of  the  administration  of  the  calcium 
compound  hypodermically  by  mouth  and  by  rectum  on 
rabbits.  In  both  groups  of  experiments  the  methyl  com- 
pound was  used.  Rekowski  found  that  there  was  almost 
immediate  restlessness;  the  mucous  membranes,  the  muzzle 
and  the  ears  became  pale  and  later  cyanosed;  the  pupils 
were  widely  dilated;  the  respirations  were  140  per  minute, 
shallow  and  diflficult;  there  were  also  involuntary  evacua- 
tions of  urine  and  feces;  paralysis  of  the  hind  limbs  came  on 
later  and  was  followed  by  paralysis  of  the  fore  limbs  and 
trunk  muscles,  and  a  sudden  and  complete  cessation  of 
respiration.  In  some  cases  after  muscular  paralysis  ap- 
peared, the  animal's  body  was  shaken  with  muscular  cramps 
and  it  died  in  opisthotonus. 

At  autopsy  the  absence  of  rigor  was  noticed  as  well  as 
the  absence  of  the  odor  of  mercaptan  in  the  tissues.  The 
blood,  liver  and  peritoneum  were  brick-red.  There  was 
rarely  hyperaemia  or  edema  of  the  lungs.  Up  to  one 
hour  after  death  the  auricles  were  still  contracting.  The  urine 
usually  contained  albumin  but  rarely  hemoglobin.  The 
blood  contained  reduced  hemoglobin,  which  rapidly  became 
oxy-hemoglobin  and  gave  a  normal  spectrum.  Rekowski 
found  the  minimal  lethal  dose  for  rabbits  to  be  0.130  gram, 
'  L.  Rekowski:  Arch.  d.  Sc.  Biol.  d.  St.  Petersbourg,  1893,  ii,  p.  205. 


20 

per  kilo  of  body  weight.  From  this  he  concludes  that 
mercaptan  is  considerably  less  toxic  than  hydrogen  sulfide. 
A  dose  of  0.03387  gram,  however,  caused  grave  symptoms 
of  intoxication,  but  the  animal  recovered  at  the*  end  of  an 
hour.  In  the  urine  the  unoxidized  sulfur  was  found  to  be 
40  per  cent,  of  the  total  sulfur,  while  usually  it  is  16.3  per 
cent. 

Herter  experimented  with  ethyl-mercaptan  on  dogs  and 
monkeys.  He  failed  to  obtain  any  symptoms  by  injecting 
on  successive  days  20,  30,  50,  56,  no,  no,  no,  no,  and 
no  cc.  of  a  o.i  per  cent,  solution  into  the  rectum  of  a  dog 
of  medium  size.  The  injection  of  50  cc.  of  0.25  per  cent, 
solution  was  not  retained  and  when  120  cc.  of  this  was 
introduced  into  the  stomach  vomiting  occm"red.  A  monkey 
failed  to  show  any  symptoms  after  the  injection  per  rec- 
tum of  10  to  30  cc.  of  a  o.i  per  cent,  solution. 

Richardson,  an  English  observer,^  was  the  first  to  ex- 
periment on  the  toxicology  of  mercaptan  and  like  many 
pioneers  was  enthusiastic  about  the  possibilities  of  his  sub- 
ject. He  says:  "In  studying  further  the  disturbances  of 
natural  zymosis  by  secondary  chemical  products  possibly 
of  peripheral  or  intestinal  origin  within  the  body  as  the  re- 
sult of  an  imperfect  or  perverted  animal  chemistry,  I 
lighted  upon  some  remarkable  facts  arising  from  the  action 
of  the  sulfuretted  organic  compounds  and  especially  from 
the  compound  generally  known  by  chemists  under  the 
name  of  mercaptan  or  sulfur  alcohol. 

"The  odor  which  is  unmistakable  emanates  from  the 
skin  and  breath  in  those  afflicted  with  dyspepsia,  typhus, 
alcoholic  gastritis,  delirium  tremens  and  small  pox. 

"On  the  blood  mercaptan  has  no  effect  but  when  in- 
haled produces  drowsiness,  muscular  fatigue,  anaesthesia 
and  nervous  and  mental  depression  which  are  so  severe 
that  if  the  inhalations  are  continued  may  end  in  self  de- 
struction." 

Richardson  concludes  that  delirium  tremens  is  due  to 
1  B.  W.  Richardson:  Aesclepiad,  London,  1889,  vi,  p.  321. 


21 

alcohol,  the  delirium  of  small  pox  and  typhus  to  some  un- 
known sulfur  product,  and  the  delirium  of  melancholia  to 
mercaptan. 

Herter'  found  that  fecal  bacteria  from  certain  patients, 
when  grown  in  a  2  per  cent,  peptone  solution  for  twenty- 
four  hours  at  37°  C,  produced  varying  quantities  of  mer- 
captan. The  amounts  obtained  may  be  summarized  as 
follows : 

Normal  persons  trace 

Babies  strong  reaction 

Constipated  persons  strong  reaction 

Pernicious  anemia  very  strong  reaction 

Marasmus  very  strong  reaction 

Depressed  mental  states  very  strong  reaction 

Fatty  diarrhea  trace 
Chronic  intestinal  indigestion    trace 

In  each  of  these  mercaptan  was  persistent  and  not 
transitory.  In  the  two  cases  of  pernicious  anemia  studied, 
the  mercaptan  disappeared  with  improvement. 

1  C.  A.  Herter:  "Bacterial  Infections  of  the  Digestive  Tract,"  1907. 


CHAPTER  II. 

COMPARISON     OF     THl^      EFFICIENCY      OF      VARIOUS      METHODS 
FOR    DETECTING   AND    DETERMINING    MERCAPTAN. — INTER- 
FERING   FACTORS. — THE     VARIOUS     MINERAL    MER- 
CAPTIDES.  — B ACTERIOIvOGICAIy   STUDIES .  — 
PHYSIOLOGICAL    OCCURRENCE    OF    MER- 
CAPTAN.— OCCURRENCE      OF      MER- 
CAPTAN   IN    DISEASE. 

The  foregoing  resume  of  the  work  that  has  been  done 
on  mercaptan  serves  to  emphasize  the  possible  importance 
of  that  substance  to  the  organism,  and  also  shows  the  in- 
completeness and  lack  of  continuity  of  these  investigations. 
Though  the  presence  of  methyl-mercaptan  has  been  recog- 
nized as  one  of  the  constituents  of  normal  urine  and  a 
method  has  been  devised  for  its  determination,  no  authority 
has  ever  determined  the  amount  present,  and  all  are  con- 
tented with  the  indefiniteness  implied  by  the  term  "a 
trace."  In  regard  to  its  presence  in  pathological  urines 
the  work  done  has  been  even  less  satisfactory. 

On  distillation  of  urine  a  number  of  volatile  sulfides  are 
given  off.     If  we  represent  that  organic  radical  to  which 
the  sulfur  in  the  volatile  sulfide  is  attached,  by  the  letter 
R,  we  have  the  following  groups  of  sulfides: 
H.  R. 

/S  yS;  for  example,  ethyl  sulfide 

H/  R/ 

hydrogen 
sulfide 
R— S 


R— S 
disulfide 


and  R — S — H  or  mercaptans 


These  different  sulfides  seem  to  be  present  in  varying 
amounts  depending  upon  the  putrefactive  process  taking 
place  in  the  organism,  and  in  definite  amounts  depending 
upon  the  "wear  and  tear"  processes  in  the  organism.     The 


23 

sulfides  arising  from  putrefactive  changes  are  pathological, 
those  due  to  normal  body  processes  are  physiological. 

In  normal  urines  sulfides  are  barely  perceptible,  whereas 
in  some  pathological  urines  they  form  a  considerable  part 
of  the  total  sulfur  content.  The  mercaptan  is  closely 
associated  with  the  other  sulfides,  and  special  means  have 
to  be  used  to  separate  it  from  the  rest,  and  bring  it  into 
a  state  in  which  it  can  be  determined. 

This  investigation,  therefore,  resolves  itself  into  a  double 
problem — one  which  has  to  do  with  the  volatile  sulfides 
in  general,  and  the  other  which  concerns  itself  specifically 
with  one  of  their  number,  mercaptan.  The  former  has 
been  approached  only  in  its  relationship  to  the  latter,  and 
ofiFers  a  fruitful  field  for  future  research. 

The  first  experiments  were  aimed  at  testing  the  avail- 
ability of  the  different  methods  for  the  separation  and  de- 
tection of  mercaptan.  In  these  series  the  method  of  Nencki 
and  Sieber  was  used.  The  following  experiments  are  typ- 
ical examples  of  the  results  obtained  from  numerous  in- 
vestigations in  each  series: 

Series  I.  Dog  urine. — 500  cc.  of  fresh  dog  urine  to  which 
oxalic  acid  had  been  added  were  distilled  through  an  or- 
dinary Liebig  condenser  with  rubber  connections  into  a 
three  per  cent,  solution  of  mercuric  cyanide.  A  greenish 
discoloration  of  the  mercuric  cyanide  solution  resulted  and 
later  on  a  light  brownish  granular  precipitate  formed. 
The  solution  was  set  aside  and  the  precipitate  allowed  to 
settle  for  twelve  hours.  During  the  distillation  there  was 
no  odor  of  mercaptan,  but  a  slight  odor  of  hydrocyanic 
acid  from  the  solution.  The  possible  reactions  that  may 
have  taken  place  can  be  represented  as  follows,  depending 
upon  the  sulfide  with  which   the  cyanide  interacted: 

(i)   2C2H5SH  -f  Hg(CN)2     =      (C2H5S)2Hg  +  2HCN 

(2)  H2S     +     Hg(CN)2       =  HgS         +  2HCN 

(3)  (C2H6)2S  +  Hg(CN)2     =         HgS     -f  2C2H5CN 

The  preceding  experiment  was  repeated,   but  instead   of 


24 

using  fresh  urine,  old,  unpreserved  dog  urine  was  used. 
A  black  granular  precipitate  was  obtained  in  the  mercuric 
cyanide  solution.  The  precipitate  was  considerably  heavier 
than  the  one  which  resulted  from  fresh  urine.  This  in- 
creased amount  of  volatile  sulfides  probably  means  that 
bacterial  or  other  influences  have  changed  the  urinary 
sulfur  constituents  to  the  sulfide  or  mercaptide  state. 
This  bacterial  action  may  take  place  in  several  ways.  It 
may  be  a  simple  reduction  of  an  oxidized  sulfur  compound, 
or  the  special  action  of  certain  bacteria,  as  the  B.  disul- 
furicans,  may  have  caused  sulfide  formation. 

These  experiments  were  repeated  with  urines  to  which 
thymol  or  chloroform  had  been  added  as  a  preservative 
agent.  These  substances  act  very  efficiently,  for  even  after 
a  week's  standing,  the  urines  behaved,  as  far  as  the  volatile 
sulfides  go,  like  freshly  voided  dog  urine. 

Series  II.  Human  urine. — About  one  liter  of  freshly 
voided  human  urine  was  treated  with  oxalic  acid  and  dis- 
tilled through  a  Liebig  condenser,  and  the  vapor  was  col- 
lected in  75  cc.  of  a  3  per  cent,  solution  of  mercuric 
cyanide.  A  very  slight,  brownish  yellow  precipitate  formed 
in  the  mercuric  cyanide  solution  which  turned  a  greenish 
tinge.  This  experiment  was  repeated  with  urine  that  had 
been  long  standing  unpreserved,  as  well  as  with  urines  that 
had  been  preserved.  The  yield  of  volatile  sulfides  obtained 
from  the  distillation  of  human  urine  appears  to  be  not 
more  than  one-sixth  as  great  as  that  obtained  from  dog 
urine. 

It  was  realized  that  very  small  amounts  of  the  sought- 
for  substances  were  present  in  any  case,  and  it  was  feared 
that  the  sulfur  constituent  contained  in  the  rubber  con- 
nections of  the  condenser,  etc.,  might  provide  a  source  of 
error  in  the  ultimate  determinations.  A  special  apparatus 
was  designed  and  constructed  which  had  glass  connections 
throughout.  This  proved  most  serviceable  and  was  used 
in  all  the  subsequent  investigations. 

Series    III.     a.   Two    cubic    centimeters    of    ethyl-mer- 


25 

captan^  were  added  to  one  liter  of  distilled  water  and  the 
whole,  with  the  addition  of  oxalic  acid,  was  distilled  into 
loo  cc.  of  a  3  per  cent,  solution  of  mercuric  cyanide. 
A  heavy,  greyish  white,  waxy  precipitate  soon  appeared 
and  continued  to  descend  for  two  hours,  when  the  dis- 
tillation vifis  stopped.  During  the  experiment  there  was 
present  a  very  strong  odor  of  mercaptan,  showing  that  the 
mercuric  cyanide  did  not  completely  absorb  the  gas.  On 
microscopical  examination  the  substance  precipitated  was 
found  to  consist  of  a  powder  without  any  characteristic 
form.  On  account  of  the  lack  of  a  crystalline  form  of  the 
mercuric  cyanide  precipitate  which  would  aiford  a  clue  to 
its  identification  on  direct  examination,  the  following  ex- 
periments were  made  in  which  other  salts  than  those  of 
mercury  were  used. 

b.  The  experiment  was  repeated.  The  distillate  was 
collected  in  a  3  per  cent,  solution  of  lead  acetate.  A 
heavy,  yellowish  precipitate  resulted  which  on  filtering  and 
examining  microscopically  showed  the  characteristic  grayish 
yellow  plates  with  irregular  edges  of  lead   mercaptide. 

c.  The  experiment  was  again  repeated,  and  the  distillate 
was  collected  in  a  solution  of  bismuth  nitrate.  A  heavy, 
brownish  black  precipitate  resulted,  which  on  microscopical 
examination  showed  very  definite  small  needles  of  bismuth 
mercaptide. 

d.  The  substitution  of  a  3  per  cent,  solution  of  ferric 
chloride  for  the  mercuric  cyanide  solution  did  not  give  any 
satisfactory  results  at  all.  The  ferric  chloride  did  not  com- 
bine well  with  mercaptan  and  the  amount  of  the  resulting 
precipitate  was  very  small. 

e.  When  zinc  chloride  was  substituted  for  mercuric  cya- 
nide there  was  some  escape  of  the  mercaptan;  but  a  grayish 
precipitate  formed  which  showed,  under  the  microscope,  the 
well-defined    narrow   quadrilaterals   of   zinc   mercaptide. 

/.  In  another  series  of  experiments,  gold  chloride  solution 

'  Ethyl-mercaptan  was  obtained  in  10  cc.  quantities  in  sealed  glass 
tubes. 


26 

was  used  instead  of  mercuric  cyanide.  A  heavy,  yellow 
precipitate  resulted,  which  on  examination  with  the  micro- 
scope showed  the  regular  plates  and  prisms  of  gold  mer- 
captide. 

It  was  found  in  all  of  these  experiments  that  none  of  the 
salts  used  combined  with  the  facility  exhibited  by  mer- 
curic cyanide.  But  as  the  quantity  of  mercaptan  present 
in  the  urine  would  under  any  circumstances  be  very  small, 
it  was  thought  that  the  advantage  of  the  ease  of  detection 
by  means  of  the  definite  crystals  would  counterbalance 
this  lack  of  combining  power.  In  the  use  of  gold  chloride 
there  is  theoretically  an  additional  advantage,  in  that  the 
gold  mercaptide  formed  in  the  distillation  is  said  to  be 
(according  to  certain  authors)  soluble  in  acetone,  whereas 
all  authorities  agree  as  to  the  general  insolubility  of  the 
other  mercaptides.  It  was,  therefore,  hoped  that  thorough 
washing  of  the  gold  sulfide  precipitate  with  acetone  would 
dissolve  out  the  mercaptide  constituent  and  by  means  of 
evaporation  and  recrystallization  a  qualitative  and  quanti- 
tative method  would  be  furnished  for  its  detection  and  esti- 
mation. 

In  spite  of  numerous  attempts,  however,  with  urines  to 
which  mercaptan  had  been  added,  the  gold  mercaptide 
crystals  were  never  obtained  by  acetone  extraction.  Gold 
mercaptide  was  found  to  be  quite  as  insoluble  in  acetone 
as  the  other  mercaptides. 

When  urine  is  distilled  directly  into  solutions  of  zinc, 
lead  or  bismuth  salts  there  is  a  very  heavy  carbonate  for- 
mation which  would  be  hard  to  get  rid  of,  and  would  pro- 
vide a  serious  source  of  error  in  the  sulfide  determinations. 

These  substances  were,  therefore,  discarded  and  the 
following  series  of  experiments  were  undertaken  with  a 
view  to  the  determination  of  the  availability  of  mercuric 
cyanide.  Mercuric  cyanide  was  found  to  be  suitable  when 
small  amounts  of  mercaptan  were  present.  When  that  sub- 
stance was  in  concentration  equal  to  a  o.oi%  solution,  how- 
ever, the  mercuric  salt  could  not  retain  it.     As   the  problem 


27 

dealt  with  small  amounts  and  as  no  better  method  could  be 
devised,  the  mercuric  cyanide  distillation  was  retained. 

The  precipitates  were  collected,  dried  for  24  hours  at  a 
temperature  of  80-90°  C.  and  weighed.^ 

The  high  temperatures  at  which  the  precipitates  were 
dried  did  not  seem  to  cause  any  loss  through  volatilization, 
for  at  no  time  was  there  the  slightest  trace  of  an  odor  of 
sulfuretted  hydrogen.  In  order  to  verify  this  observation 
a  number  of  precipitates  were  dried  at  a  lower  temperature 
and  for  longer  periods.  These  controls  gave  approximately 
the  same  results  for  normal  urine  as  the  former,  so  the 
precipitates  from  the  pathological  specimens  were  dried  at 
the  higher  temperature. 

In  order  to  accomplish  the  separation  of  mercaptan  from 
the  other  sulfides,  the  following  process  was  employed: 
The  hard  filter  paper  containing  the  sulfide  precipitate  was 
placed  in  a  small  flask  containing  some  water.  This  flask 
was  connected  by  means  of  a  glass  tube  with  another 
flask  containing  50  cc.  of  a  3  per  cent,  lead  acetate  solu- 
tion. To  the  flask  containing  the  precipitate  there  were 
added  50  cc.  of  a  10  per  cent,  acetic  acid  solution  and 
25  cc.  of  5  per  cent,  hydrochloric  acid  slowly  through  a 
thistle  tube.  The  flask  was  then  heated  very  slightly  for 
an  hour,  a  period  during  which,  if  mercaptan  is  present,  the 
yellow  precipitate  of  lead  mercaptide  will  form  in  the  lead 
acetate  solution,  and  the  crystals  may  be  identified  and 
weighed. 

1  The  determinations  in  the  urine  are  in  terms  of  methyl-mercaptan, 
as  that  is  the  compound  generally  considered  to  be  present.  As  the  second 
or  mercaptan  distillation  is  made  into  lead  acetate  and  the  substance  ob- 
tained is  lead  mercaptide  the  determination  is  made  by  the  following 
proportion : 

(C2H6S)2Pb  :  CH3SH  =  wt.  of  lead  mercaptide  :  x 
382  48 

In  the  experiments  in  which  ethyl-mercaptan  was  given  directly  to  a  dog 
the  values  obtained  are  in  terms  of  that  substance;  thus, 

(CjHiSjsPb  :  C.HiSH  =  wt.  of  lead  mercaptide  :  x 
382  62 


28 

This  was  generally  the  method  that  was  followed  and  is 
so  far  the  most  reliable  means  for  the  quantitative  determi- 
nation of  mercaptan.  Care  should  be  taken  to  filter  the 
lead  acetate  solution  through  a  double  filter  paper,  and  to 
filter  the  lead  acetate  plus  the  lead  mercaptide  at  once  after 
the  distillation  is  completed  for  fear  of  a  reprecipitation  of 
the  lead  acetate.  As  very  small  amounts  of  mercaptan  are 
present  these  precautions  are  most  necessary. 

Both  the  mercuric  sulfide  and  lead  mercaptide  precipi- 
tates should  be  freed  as  far  as  possible  from  complicating 
substances  by  thorough  washing  with  distilled  water. 

The  following  series  of  experiments  were  aimed  at  the 
determination  of  the  mercaptan  content  in  normal  human 
urine,  dog  urine  and  human  feces.  The  human  urine  was 
collected  from  students  in  this  laboratory  and  freshly  distilled; 
that  of  the  dog  was  from  an  animal  on  a  general  diet;  and 
the  feces  were  procured  from  hospital  patients  suffering  from 
slight  surgical  distmrbances  which  would  not  be  likely  to 
be  associated  with  active  protein  decomposition  or  intestinal 
putrefaction. 

Series  IV. — The  following  table  will  show  the  amount 
of  volatile  sulfides  and  mercaptan  in  normal  human  urine. 
The  determinations  of  the  sulfides  are  in  terms  of  hydrogen 
sulfide  and  those  of  mercaptan  in  terms  of  the  methyl- 
thio-alcohol. 

Mercaptan  and  Volatile  Sulfides  in  Normal  Human  Urine. 


Amount   of   urine. 

Volatile   sulfide. 

Mercaptan. 

Cc. 

Gm. 

Gm. 

lOOO 

O.GG28 

none 

I  GOG 

G . GG24 

none 

IGGG 

G . GG25 

none 

IGGO 

G.GG29 

none 

IGGG 

G.GG23 

none 

IGGG 

G.GG32 

none 

IGGG 

O.GG28 

none 

IGGG 

G.OG26 

none 

From  the  above  analyses  it  will  be  seen  that  there  is  no 
mercaptan  in  normal,  freshlv  voided  human  urine. 


mount. 

Volatile  sulfides. 

Cc. 

Gm. 

470 

o.ooSj 

450 

0 . 0092 

480 

0.0076 

475 

0 . 0079 

470 

0 . 0085 

29 

The  following  table  will  show  the  figures  obtained  on 
the  analyses  of  dog  urine: 

Mercapian   and   Volatile  Sulfides  in   Dog  Urine. 

Mercaptan. 
Gm. 

trace 
0.0018 
trace 
trace 

0.0014 

The  volatile  sulfides  in  the  twenty-four  hour  urine  of 
dogs  are  more  than  six  times  the  quantity  of  sulfides  pres- 
ent in  an  equal  amount  of  human  urine.  Mercaptan  is 
constantly  present  in  dog  urine.  In  the  above  determi- 
nations less  than  a  milligram  of  mercaptan  was  considered 
"a  trace."  These  findings  in  regard  to  the  volatile  sulfides 
in  dog  urine  are  in  direct  confirmation  of  the  results  ob- 
tained  by   Abel.^ 

The  feces  examined  were  normally  formed  human  stools. 
The  feces  were  mixed,  un weighed,  with  a  liter  of  distilled 
water;  oxalic  acid  was  added  to  acid  reaction,  and  the 
whole  was  then  distilled  as  in  the  urine  examination.  The 
fecal  distillates  differ  in  appearance  from  those  obtained 
from  urine  distillation.  The  former  resemble  the  precipi- 
tate which  is  formed  in  passing  a  stream  of  hydrogen  sul- 
fide into  a  solution  of  mercuric  cyanide,  that  is,  the  pre- 
cipitates are  blackish  brown  and  at  once  sink  to  the  bot- 
tom, whereas  the  urinary  precipitates  are  grayish  brown  and 
at  first  float  near  the  top  of  the  mercuric  cyanide  solution. 
This  difference  in  physical  character  is  doubtless  due  to 
the  preponderance  of  hydrogen  sulfide  in  the  fecal  distil- 
lates. 

The  accompanying  table  will  show  the  figures  obtained  for 
volatile  sulfides  and  mercaptan  in  normal  human  feces, 
freshly  passed: 

1  Abel:  Johns  Hopkins  Hosp.  Bull.,  1894,  v,  p.  123. 


30 

Volatile  Sulfides  and  Mercaptan  in  Human  Feces. 

Volatile  sulfides. 

Gm.  Mercaptan. 

0.0135  none 

0.0120  none 

0.0128  none 

0.0125  none 

0.0167  none 

0.0172  none 

0.0132  none 

0.0134  none 

The  above  experiments,  as  has  been  stated  before,  were 
with  fresh  human  feces.  With  feces  that  had  been  allowed 
to  stand  for  a  long  time  before  examination,  different  re- 
sults were  obtained.  In  one  case  a  jar  of  feces  was  allowed 
to  stand  for  three  summer  months;  upon  opening 
the  jar  a  strong  odor  of  mercaptan  was  perceptible.  The  lead 
mercaptide  precipitate  was,  through  oversight,  not  weighed. 

These  investigations  on  human  feces  bear  out  Herter's 
contention  that  mercaptan  is  not  present  in  normal  fresh 
specimens  of  human  feces. 

The  preceding  experiments  on  dog  urines  were  made  on 
animals  which  received  an  indefinite  diet.  The  following 
experiments  on  dogs  were  made  with  controlled  diets. 

Series  V. — A  ten-kilogram  dog  was  kept  in  one  of  the 
cages  which  have  long  been  in  constant  use  in  this  labora- 
tory.'^ The  animal  was  fed  on  a  rich  protein  diet,  i.  e.,  48 
grams  of  nitrogen  daily.  The  urines  were  collected  every 
day  and  examined  for  volatile  sulfides  and  mercaptan.  The 
following  figures  show  the  results  obtained  in  four  con- 
secutive days: 

Volatile  Sulfides  and  Mercaptan  in  the  Urine  of  a  Dog  Fed  on  a 
Rich  Protein  Diet. 


Amount  of  urine. 

Volatile  sulfides. 

Mercaptan. 

Cc. 

Gm. 

Gm. 

455 

0.0095 

trace 

450 

0 . 0090 

trace 

450 

0 . 0080 

trace 

445 

0 . 0090 

0.0012 

1  Gies;  American  Jour.  Physiol.,  1905,  xv,  p.  403. 


31 

The  same  dog  was  then  fed  for  a  period  of  five  consecu- 
tive days  on  a  poor  protein  diet,  that  is,  it  received  8  grams 
of  nitrogen  daily.  The  urines  were  then  collected  and 
analyzed  for  volatile  sulfides  and  for  mercaptan. 

Volatile  Sulfides  and  Mercaptan  in  the  Urine  of  a  Dog  Fed  on  a 
Poor  Protein  Diet. 


Amount  of  urine. 

Volatile  sulfides. 

Cc. 

Gm. 

Mercaptan, 

445 

000095 

trace 

455 

0 . 0089 

trace 

450 

0 . 0090 

trace 

450 

0.0088 

trace 

455 

0.0092 

trace 

The  volatile  sulfides  and  the  mercaptan  seem  to  be  un- 
influenced by  the  high  or  low  protein  diet.  They  run  a 
similar  course  to  the  larger  unoxidized  sulfur  constituent  of 
which  they  form  a  part. 

While  the  methods  described  for  the  determination  of 
mercaptan  are  fair  laboratory  procedures,  still,  as  it  was 
thought  likely  that  mercaptan  may  be  of  clinical  patho- 
logical significance,  attempts  were  made  to  improvise  a 
method  that  would  be  less  cumbersome. 

Isatin  dissolved  in  concentrated  sulfuric  acid  forms  a 
red  solution  which  is  colored  olive-green  by  mercaptan. 
The  solution  of  isatin  used  was  made  up  freshly  in  each 
case :  0.05  gram  of  isatin  was  dissolved  in  i  cc.  of  concen- 
trated  sulfuric  acid. 

Series  VI. — It  was  found  that  the  common  preserva- 
tives of  urine,  such  as  thymol  and  chloroform,  produce  a 
deep  red  color,  resembling  the  color  of  raspberry  juice, 
when  added  to  the  isatin  solution.  In  all  cases,  therefore, 
it  is  important  to  examine  the  urine  when  quite  fresh,  for 
the  use  of  a  preservative  is  not  permissible. 

Neither  normal  dog  urine  nor  human  urine  when  directly 
added  to  isatin  solution  gives  a  positive  reaction.  It  was 
also  found  that  upon  treating  the  distillate  obtained  from 
dog  or  human  urine  with  isatin  a  negative  result  was  ob- 


32 

tained.  But  this  does  not  prove  the  absence  of  mercaptan 
as  the  following  experiments  will  show: 

One  liter  of  water  containing  one  cubic  centimeter  of  a 
I  per  cent,  aqueous  solution  of  ethyl-mercaptan  was  dis- 
tilled (after  the  addition  of  some  oxalic  acid)  directly  into 
the  isatin  solution.  A  negative  reaction  was  obtained. 
If,  however,  instead  of  using  i  cc.  of  a  i  per  cent,  ethyl- 
mercaptan  solution,  2  cc.  were  used,  a  positive  reaction 
was  obtained. 

With  dog  or  human  urines  it  was  found  that  with  the  ad- 
dition of  2  cc.  of  a  I  per  cent,  solution  of  ethyl-mercaptan 
to  looo  cc.  of  urine  and  then  distilling  into  isatin,  a  nega- 
tive result  was  obtained.  In  these  cases  it  was  found 
necessary  to  add  3  cc.  of  a  i  per  cent,  aqueous  solution 
of  ethyl-mercaptan  to  a  liter  of  dog  or  human  urine  be- 
fore the  distillate  gave  a  positive  reaction  with  the  isatin- 
sulfuric  acid  solution.  From  these  observations  we  must 
conclude  that  the  isatin-sulfuric  acid  reagent  is  not  suffi- 
ciently delicate  to  employ  as  a  means  for  the  detection  of 
mercaptan  in  very  small  quantities.  It  is  a  good  quali- 
tative test  when  the  amount  of  mercaptan  is  large.  ^ 

It  has  been  observed  that  iodine  solutions  oxidize  mer- 
captans  to  the  disulfide  state,  and  it  was  thought  that, 
perhaps,  this  reaction  may  be  made  available  for  the  de- 
termination of  the  thio-alcohol.  The  reaction  can  be  ex- 
pressed by  the  following  equation: 

2RSH  -j-  I2  =  R— S— S— R  +  2HI 

In  all  the  determinations  25  cc.  of  N/ioo  iodine  solution 
were  used,  and  the  loss  was  determined  by  titrating  with 
N/100  sodium  thiosulfate  solution  after  the  addition  of  a. 
few  drops  of  soluble  starch  as  an  indicator.  Very  many  ex- 
periments were  performed  with  the  object  of  ascertaining 
whether     this     method     gave     reliable     results.       It     was 

^  It  must  be  remembered  that  other  sulfur  derivatives,  as,  for  example, 
thiophene,  produce  colorations  with  isatin;  and  these,  if  present,  will  be 
complicating  factors. 


33 

found,  in  general,  unreliable,  for  there  are  other  substances 
in  the  urine  that  will  reduce  iodine. 

Series  VII. — The  following  series  of  experiments  were 
undertaken  in  order  to  determine  the  amounts  of  volatile 
sulfides  and  mercaptan  present  in  the  urine,  when  the  thio- 
alcohol  is  administered  to  the  dog  per  os.  A  dog  weighing 
ten  kilos  was_  kept  in  a  cage  and  fed  on  a  mixed  diet  of 
meat,  crackermeal,  lard,  bone  ash  and  water.  The  dog 
received  daily  doses  of  mercaptan;  the  urine  was  collected 
and  analyzed. 

Volatile  Sulfides  and  Mercaptan  in  the  Urine  oj  a  Dog  Fed  with 
Mercaptan. 

Volatile  sulfides.  Mercaptan. 

Gm.  Gm. 

0.0134  0.0038 

0.0160  0.0040 

0.0152  0.0049 

0.0188  0.0068 

0.0157  0.0044 

0.0155  0.0045 

No  dose  of  more  than  two-tenths  of  a  gram  was  toler- 
ated, and  the  dog  vomited  when  this  dose  was  repeated. 
It  was  found,  as  will  be  seen  from  the  above  table,  that  the 
administration  to  a  dog  of  mercaptan  in  the  food  caused 
a  very  marked  increase  in  the  volatile  sulfides  and  mer- 
captan output  in  the  urine,  but  only  a  small  fraction  of 
the  mercaptan  administered  appeared  in  the  urine  as  it  was 
eliminated  in  great  part  by  the  breath. 

Series  VIII.  Bacterial  formation  of  mercaptan. — The  work 
previously  done  on  the  mercaptan-forming  capacity  of 
certain  bacteria  of  the  intestinal  tract  has  been  fairly 
thorough  especially  in  relation  to  the  B.  putrificus.  The 
proteus  group,  however,  several  members  of  which  are  com- 
mon inmates  of  the  alimentary  canal,  has  been  more  or 
less  neglected  in   this  connection. 

This  series  of  experiments  was  undertaken  with  a  view 
to  establishing  the  mercaptan-forming  ability  of  a  very 
common  member  of  the  proteus  group,  B.  proteus  vulgaris. 


Dose  mercaptan. 

Urine. 

Gm. 

Cc. 

0.  I 

720 

0.15 

510 

0.15 

535 

0.2 

420 

0.15 

572 

0.15 

505 

34 

Cultures  of  this  bacillus  grown  on  a  peptone  medium  were 
employed.  A  number  of  tubes  on  the  style  of  Einhorn 
saccharometers  were  filled  in  the  following  manner:  Tube 
number  i  received  lo  cc.  of  the  peptone  culture  of  the 
B.  proteus  vulgaris  and  o.i  gram  of  solid  cystin;  tube 
2,  9  cc.  of  the  peptone  culture  and  i  cc.  of  a  0.05  per 
cent,  suspension  of  cystin  in  water;  tube  3,  8  cc.  of  the 
culture  and  2  cc.  of  the  cystin;  suspension  tube  4,  6  cc.  of  the 
culture  and  4  cc.  of  the  cystin  suspension.  All  the  fer- 
mentation tubes  were  incubated  at  38°  C.  In  48  hours 
there  was  gas  formation  in  all  the  tubes  except  number  i. 
In  72  hours  this  also  showed  the  presence  of  gas  in  the  long 
arm  of  the  tube.  The  gas  in  tubes  2,  3,  and  4  smelt 
strongly  of  mercaptan.  Tube  number  i  smelt  of  hydrogen 
sulfide  rather  than  of  mercaptan. 

This  experiment  was  modified.  A  flask  was  connected 
by  means  of  glass  tubes  so  that  any  escaping  gas  would  be 
collected  in  a  solution  of  isatin  in  sulfuric  acid.  The  flask 
was  filled  with  50  cc.  of  the  peptone  culture  of  the  proteus 
vulgaris  and  o.i  gram  of  cystin.  At  the  end  of  48  hours 
in  the  incubator  the  isatin-sulfuric  acid  was  tinged  with 
green,  and  at  the  end  of  72  hours  was  entirely  green. 

The  above  results  were  also  obtained  when  the  flask  was 
kept  at  room  temperature.  However,  96  hours  were  re- 
quired in  this  case  to  change  the  isatin-sulfuric  acid.  We  must 
conclude  from  these  experiments  that  the  B.  proteus  vulgaris 
undoubtedly  possesses  the  faculty  of  splitting  mercaptan  from 
the  cystin  molecule.  This  process  is  not  very  rapid,  how- 
ever, in  vitro.  The  bacillus  acts  more  strongly  when  the 
cystin  is  in  solution  or  in  very  dilute  suspension. 

The  Occurrence  of  Mercaptan  in  Disease. — It  has  been 
suggested  by  one  author^  that  mercaptan  plays  an  import- 
ant role  in  the  depressed  or  lowered  mental  states.  It 
was,  therefore,  thought  proper  to  begin  a  study  of  the 
occurrence  of  mercaptan  in  certain  forms  of  insanity.  The 
following  results  were  obtained: 

^  Richardson:  Aesclepiad,  London,  1889,  vi,  p.  321. 


35 

Volatile  Sulfides  and  Mercaptan  in  Cases  of  Insanity. 
I.  Depressive  Mania. 


Amount  of  urine. 

Volatile  sulfides. 

Cc. 

Gm. 

Mercaptan. 

1230 

0.0019 

none 

1400 

0.0028 

none 

65o(?) 

0.0016 

none 

1475 

0.0025 

none 

- 

2.  Exalted  Mania. 

Amount  of  urine. 

Volatile  sulfides. 

Cc. 

Gm. 

Mercaptan. 

1420 

0.0028 

none 

1560 

0.0032 

none 

1485 

0.0030 

none 

From  these  results  we  see  that  there  is  no  variation  from 
the  normal  as  far  as  the  mercaptan  goes  in  the  cases  of 
dementia  studied. 

In  toxemia  of  pregnancy  owing  to  the  severe  disturbances 
in  the  metabolism,  it  was  thought  likely  that  some  change 
would  be  observed  in  the  mercaptan  output.  We  must 
classify  these  cases  into  two  types:  those  that  are  so  severe 
that  they  have  only  a  fatal  termination,  and  those  cases 
which  are  quite  mild  or  recover  completely  from  this 
disease.  The  accompanying  table  will  show  the  results  ob- 
tained. No  variations  from  the  normal  were  observed  in 
the  mercaptan  output  in  these  cases.  The  output  of  vol- 
atile sulfides  was  increased  in  two  cases. 
Volatile  Sulfides  and  Mercaptan  in  Cases  of  Mild  Toxemia  of 

Pregnancy. 


Amount  of  urine. 

Volatile  sulfides. 

Case. 

Cc. 

Gm. 

Mercaptan. 

I  . 

1530 

0.0042 

none 

I5IO 

0.0032 

none 

1525 

0.0035 

none 

2. 

1260 

0.0080 

none 

834(?) 

0.0040 

none 

1255 

0.0073 

none 

3- 

1342 

0.0072 

none 

In    one    severe    case,    however,    which    terminated   fatally 
the  urine  showed  distinct  traces  of  mercaptan.     The  follow- 


36 

ing  figures  will  indicate  the  results  obtained  on  five  con- 
secutive  days. 

Excretion  of  Mercaptan  in  Fatal  Eclampsia. 


Amount  of  urine. 

Mercaptg.n 

Day. 

Cc. 

Gm. 

I  . 

780 

0.0022 

2. 

620 

0.0017 

3- 

685 

0 . 002  I 

4- 

580 

0 . 0024 

5- 

840 

0.0019 

In  chronic  interstitial  and  chronic  parenchymatous 
nephritis  the  same  results  were  obtained  as  in  the  mild 
cases  of  eclampsia.     There  was  no  mercaptan  in  the  urine. 

Volatile  Sulfides  and  Mercaptan  in  Chronic  Nephritis. 
I.  Chronic  Interstitial  Nephritis. 


Amount  of  urine. 

Volatile  sulfides. 

Case. 

Cc. 

Gm. 

Mercaptan. 

I  . 

1465 

0 . 0085 

none 

1520 

0 . 0070 

none 

1528 

0 . 0089 

none 

2. 

1380 

0 . 0060 

none 

1365 

0.0055 

none 

1375 

0 . 0064 

none 

3- 

1535 

0.0095 

none 

1520 

0 . 0086 

none 

1545 

0 . 0089 

none 

2. 

Chronic   Parenchymatous   Nephritis. 

Amount  of  urine. 

Volatile  sulfides. 

Case. 

Cc. 

Gm. 

Mercaptan 

I  . 

860' 

0.0120 

none 

930 

O.OII4 

none 

2. 

1034 

0.0052 

none 

1 140 

0 . 0080 

none 

1032 

0 . 0086 

none 

Lobar  pneumonia  was  especially  studied  for  the  mer- 
captan output.  Karplus^  had  reported  that  he  had  found 
mercaptan   in    a   case   of   pneumonia.     It   was   found    that 

^  Karplus:  Virchow's  Archiv.,  1893,  cxxxvi,  p.  210. 


37 

there  was  a  difference  in  the  mercaptan  output  before 
crisis  and  after  crisis.  Pneumonia  is  a  disease  which  is 
especially  characterized  by  an  increased  fibrin  content  of 
the  blood.  In  the  pathological  process  of  pneumonia  this 
fibrin  is  deposited  in  the  alveoli  of  the  lungs.  When  the 
stage  of  resolution  sets  in  the  fibrin  is  broken  down,  ab- 
sorbed and  the  products  of  decomposition  are  excreted. 
It  was  found,  as  will  be  observed  on  examination  of  the 
accompanying  table,  that  mercaptan  was  present  in  the 
pneumonic   patients   after   crisis. 

Volatile  Sulfides  and  Mercaptan  in  the  Urine  of  Lobar  Pneu- 
monic  Patients. 

Am.  of  urine.     Volatile  sulfides.       Mercaptan. 


Case.            Stage. 

Cc. 

Gm. 

Gm. 

I .  Before  crisis 

1465 

0 . 0048 

none 

1470 

0.0054 

none 

1460 

0 . 0044 

none 

After  crisis 

1320 

0.0190 

0.0018 

1260 

0.0195 

0.0024 

I3IO 

0.0225 

0.0020 

1395 

0 . 0200 

0.0014 

Atnt.  of  urine. 

Volatile  sulfides. 

Case.            Stage. 

Cc. 

Gm. 

Mercaptan. 

I4IO 

0.0125 

trace 

1435 

0.0162 

trace 

1460 

0.0154 

none 

2 .  Before  crisis 

1530 

0.0063 

none 

1535 

0.0073 

none 

1537 

0 . 0080 

none 

After  crisis 

1525 

0.0192 

trace 

1528 

0.0184 

trace 

1520 

0.0176 

none 

It  was  thought  advisable  to  make  several  sulfur  par- 
titions in  cases  of  pneumonia,  in  order  to  observe  the  re- 
lation of  mercaptan  to  the  other  sulfur  compounds.  Three 
cases  were  studied.  The  following  table  will  show  the 
figures   obtained : 


38 


Sulfur  Partitions  in  Lobar  Pneumonia. 

Am.  of  urine.  Case  1.  Case  2. 

ii6o  CO. 
2.0556  gm. 
0.83   gm. 


1475  cc. 
1.2875  gm. 
0.45   gm. 

34-8 


Amount  of  urine 
Total  sulfur^ 
Sulfate  sulfur 
Sulfate  sulfur 

%  of  total  sulfur 
Ethereal  sulfate  S 

%  total  sulfur  4.6 

Neutral  S 

%  of  total  sulfur  12.5 

Inorganic  sulfate  S 

%  of  total  sulfur  82.9 

Potassium  sulfocyanate2o.oio8  gm. 
Mercaptan  0.0021  gm 

Volatile  sulfides  0.014  gm . 


40.4 

8.4 

17.4 

74.2 

0.0114  gm. 
absent 
0.0163  gm. 


Case  3. 
780  CC. 
1.8749  gm. 
0.56      gm. 

30.01 

5-7 
16.9 

77-4 

0.0064  gm. 
trace 
0.0324  gm. 


In  several  cases  of  carcinoma  and  sarcoma  of  the  in- 
testinal tract,  mercaptan  was  found  only  in  one  case  which 
was  very  advanced  and  was  considered  entirely  inoperable. 
The  following  table  explains  itself: 

Volatile  Sulfide  and  Mercaptan  in  the  Urine  oj  Cases  of  Malig- 
nant Disease. 


Volatile 

Am.  of  urine. 

sulfides. 

Diagnosis. 

Cc. 

Gm. 

Mercaptan. 

Cancer  of  pylorus  and  les- 
ser curvature 

lOIO 

0.0285 

0.0037 

1220 

0 . 0300 

0 . 0042 

Cancer  of  pylorus 

1210 
1540 

0.0364 
0.0058 

0.0040 

none 

Cancer  of  esophagus 

1535 
1554 
1580 

0 . 0049 
0.0058 
0.0045 

none 
none 
none 

Sarcoma  of  small  intestine 

1585 
1595 
1655 

0 . 0040 
0 . 0048 
0.0207 

none 
none 
none 

4- 


1  The  total  sulfur  was  determined  by  the  Benedict  method,  the  various 
sulfates  by  the  Folin  method,  the  sulfocyanate  by  the  Rupp,  Schied  and 
Thiel  method. 

^  Expressed  in  terms  of  KSCN. 


39 

In  case  4  the  urine  contained  a  large  amount  of  indican. 
Case  2  was  an  operable  case. 

In  a  case  of  pyelitis  and  cystitis  the  excretion  of  mer- 
captan  in  the  urine  was  especially  high.  The  following 
table  shows  the  figures  obtained  on  four  successive  days: 

Volatile  Sulfides  and  Mercaptan  in  the  Urine  of  Pyelitis  and 

Cystitis. 


Am.  of  urine. 

Volatile  sulfides. 

Mercaptan. 

Day. 

Cc. 

Gm. 

Gm. 

r. 

960 

0.0145 

0.0037 

2. 

1020 

0.0152 

0.0028 

3- 

1250 

lost 

0 . 0039 

4- 

1375 

0.0128 

0.0035 

In  the  urines  of  patients  suffering  with  cholelithiasis  no 
mercaptan  was  ever  found.  Many  of  these  patients  showed 
an  increase  in  the  urinary  pigments,  and  quite  frequently 
bile  pigments  were  present  in  the  urine.  But  it  seems  that 
the  biliary  constituent  of  the  urine  had  no  effect  in  in- 
creasing the  mercaptan  output. 

With  the  urines  of  diabetic  patients,  peculiar  results 
were  produced.  It  was  found  that  upon  distilling  a  freshly 
voided  specimen  of  diabetic  urine  no  mercaptan  figure  could 
be  obtained.  If  the  urine  was  allowed  to  stand  with  a  pre- 
servative hke  chloroform,  toluene  or  thymol,  and  distillation 
was  then  made,  a  negative  result  was  also  found.  If,  how- 
ever, the  urine  was  allowed  to  stand  for  three  days  without 
any  preservative  and  was  then  distilled,  a  positive  mercap- 
tan reaction  resulted.  It  was  found  that  the  quantity  of 
mercaptan  present  in  the  stale  urine  was  directly  pro- 
portional to  the  amount  of  sugar  (glucose)  excreted.  If 
the  urine  was  allowed  to  stand  for  several  days  with  the 
addition  of  a  little  yeast  the  mercaptan  production  was 
especially  marked.  The  accompanying  table  will  show  some 
of  the  figures  obtained: 


40 

Volatile  Sulfides  and  Mercaptan  Excretion  in  the  Urine  of  Dia- 
betic   Patients. 


Am.  of  urine. 

Glucose. 

Volatile  sulfides. 

Mercaptan. 

Condition  of 

Cc. 

%• 

Gm. 

Gm. 

urine. 

2650 

2.5 

0.0082 

0.0 

fresh 

2275 

2.8 

0.0092 

0.0 

fresh 

2640 

2.4 

0.0102 

0.0 

fresh 

2575 

2-3 

0.0142 

0.0025 

stale 

2445 

3-4 

0.0135 

0 . 0042 

stale 

2750 

3-9 

0.0154 

0 . 0049 

stale 

Conclusions. — Mercaptan  is  a  compound  which  may  be  pro- 
duced as  a  result  of  the  chemical  processes  in  the  human  organ- 
ism and  is  always  formed  as  the  result  of  these  processes  in  the 
dog.  It  is  not  found  in  normal  human  urine,  but  is  constantly 
present  in  that  of  a  dog.  Diet  in  which  the  sulfur  com- 
ponent is  not  raised  to  extremes  has  no  effect  on  the  mer- 
captan content  of  the  urine.  Mercaptan  bears  a  close  but 
indefinite  relationship  to  the  other  volatile  sulfides  and  may 
be  interchangeable  with  some  of  these,  notably  those  of  the  R2S 
form,  to  which  it  may  be  oxidized  and,  as  such,  excreted. 
These  transformations  and  its  rapid  elimination  by  the 
breath  prevent  the  recovery  of  any  large  amount  of  mer- 
captan from  the  urine.  Mercaptan  has  been  found  in  those 
diseases  where  severe  decomposition  is  prevalent.  Fatal 
eclampsia,  pneumonia  after  crisis,  ulcerating  carcinoma  and 
marked   cystitis  gave  positive  reactions  for  mercaptan. 

Occurrence  of  Mercaptan  in  the  Gastric  Contents  after 
Tying  of  Pylorus. — The  stomachs  of  seven  dogs  were  tied 
at  the  pylorus  in  various  ways  so  as  to  block  off  the  py- 
loric exit  and  induce  fermentation  and  stasis  of  the  gas- 
tric contents.  No  tetanoid  manifestations  were  observed 
in  the  animals,  but  as  the  putrefaction  was  marked,  it  was 
thought  advisable  to  examine  the  gastric  contents  for  the 
presence  of  mercaptan.  Each  stomach  was  placed  sepa- 
rately in  a  securely  sealed  jar  which  was  connected  with 
another  jar  containing  calcium  hydroxide  solution  and  this 
in  turn  was  connected  with  another  jar  in  which  was  mer- 
curic cyanide.     The  whole   apparatus  was   connected  with 


41 

a  suction  pump  and  the  gases  from  each  of  these  stomachs 
were  drawn  through  the  solutions.  These  gases  were  found 
to  be  carbon  dioxide  and  hydrogen  sulfide.  No  mercaptaa 
was  found  in  any  instance. 

Influence   of   mercaptan   on   enzymes. 

The  action  of  mercaptan  upon  the  common  enzymes  may, 
it  was  thought,  be  of  significance  in  establishing  its  causal 
relationship  to  certain  diseases.  In  any  case,  the  study 
of  the  thio-alcohols  would  be  incomplete  without  ascertain- 
ing their  influence   upon   these   unorganized   ferments. 

The  investigations  were  made  upon  ptyalin,  pepsin  and 
trypsin  as  types  of  animal  enzymes,  malt  diastase  as  a 
typical  vegetable  enzyme,  milk  fermentation  as  a  repre- 
sentative of  bacterial  action,  and  the  sugar-splitting  power 
of  yeast  as  a  type  of  enzyme  action  caused  by  a  fungus. 

Salivary  Amylase. — To  3  cc.  of  a  one  per  cent,  starch 
suspension  in  each  of  five  test  tubes  there  were  added 
two  cubic  centimeters  of  saliva.  To  tubes  i,  2,  3,  4,  were 
added,  respectively,  i,  2,  3,  and  4  drops  of  propyl-mer- 
captan.  Tube  5  was  used  as  a  control.  At  intervals  the 
various  tubes  were  tested  for  maltose  with  the  Benedict 
reagent.  It  was  found  that  the  mercaptan  did  not  in- 
fluence the  salivary  amylase. 

Malt  Diastase. — Similar  experiments  were  carried  out 
with  malt  diastase.  In  this  case  it  was  also  found  that 
the  mercaptan  did  not  inhibit  the  action  of  the  enzyme. 

Gastric  Protease. — Fairchild's  pepsin  was  used  in  these 
experiments.  The  proteolytic  activity  was  determined  by 
means  of  Mett  tubes.'  It  was  found  that  the  propyl-mer- 
captan  did  not  inhibit  the  action  of  the  gastric  protease 
on  the  egg  albumin. 

Pancreatic  Protease. — Similar  results  were  obtained  with 
trypsin,  that  is,  concentrations  of  propyl-mercaptan  up  to 
four  drops  in  5  cc.  of  the  solution  did  not  inhibit  the 
tryptic   digestion. 

•  Frank:  Jour.  Biol.  Chem.,  191 1,  ix,  p.  463. 


42 

Effect   of   Propyl-Mercaptan  on  Yeast  Fermentation. — A 

five  per  cent,  glucose  solution  was  put  into  a  number  of 
Binhorn  saccharometers.  To  the  various  saccharometers 
different  amounts  of  mercaptan  were  added.  A  control  tube 
to  which  no  mercaptan  was  added  was  also  used. 

A  uniform  suspension  was  prepared  of  the  best  yeast 
in  distilled  water.  To  each  saccharometer  I  added  one 
cubic  centimeter  of  this  suspension.  The  amount  of  fer- 
mentation was  determined  by  the  quantity  of  carbon  di- 
oxide produced  in  each  saccharometer. 

It  was  found  that  the  propyl-mercaptan  inhibited  the  ac- 
tion of  the  yeast  fermentation. 

Effect  of  Mercaptan  on  the  Souring  of  Milk. — To  a  num- 
ber of  test  tubes  containing  fresh  milk,  various  amounts 
of  propyl-mercaptan  were  added,  and  a  few  drops  of  lit- 
mus solution.  It  was  found  that  the  tubes  containing  the 
propyl-mercaptan  behaved  similarly  to  the  control  tubes, 
showing  that  the  thio-alcohol  did  not  prevent  the  growth 
of  the  lactic  acid  bacillus. 


CHAPTER  III. 
Pharmacology. 

In  their  relation  to  the  problem  of  autointoxication  all 
the  products  formed  from  the  decomposition  of  food  sub- 
stances in  the  intestinal  tract  are  of  interest.  Certain  of 
these  substances,  particularly  the  phenol  and  indol  groups, 
amino  acid  derivatives  of  which  are  tyrosin  and  trypto- 
phan, have  been  thoroughly  investigated  and  the  pro- 
tective methods  employed  by  the  body  against  them, 
notably  conjugation,  oxidation  and  reduction,  have  been 
carefully   studied. 

Very  little  work  has  been  done,  however,  on  a  large 
number  of  sulfur-containing  substances  which  are  chiefly 
derived  from  the  thio-amino  acid  cystin,  and  practically 
no  work  at  all  on  one  of  its  important  derivatives,  mer- 
captan. 

As  cystin  forms  a  large  part  of  the  complex  protein 
molecule  and  as  certain  of  the  common  bacteria  of  the 
intestinal  tract  have  been  found  to  be  capable  of  producing 
mercaptan  from  it,  the  study  of  mercaptans  especially  in 
relation  to  their  toxicology  possesses  more  than  a  purely 
academic  interest. 

These  pharmacologic  investigations  were  made  on  frogs, 
guinea  pigs,  and  dogs.  In  the  frogs  the  drug  was  injected 
into  the  anterior  lymph-sac,  in  the  guinea  pigs  subcuta- 
neously,  and  in  the  dogs  it  was  administered  by  mouth  in 
capsules  with  the  food.  Only  one  dog  in  six  was  found  to 
be  capable  of  tolerating  even  the  odor  of  mercaptan,  so  the 
investigations  on  that  animal  which  could  yield  the  most 
definite  results  from  a  human  standpoint  were  necessarily 
limited. 

The  studies  of  the  eff'ect  of  the  drug'  on  frogs  were  made 
during  the  winter  months  when    cold-blooded    animals  are 

'  Unless  otherwise  stated  ethyl-nu^rcaptan   was   used   in   the  experi- 
ments, because  of  the  greater  ease  of  procuring  and  handling  it. 


44 

naturally  torpid  but  are  not  more  susceptible  to  drug  action. 
In  these  animals  and  in  the  guinea  pigs  solutions  of  the 
mercaptan  in  50  per  cent,  alcohol  were  used.  Aqueous 
solutions  were  at  first  employed  as  controls,  but  as  the 
results  were  found  to  be  in  every  way  similar,  and  as  ethyl - 
mercaptan  is  only  slightly  soluble  in  water  (i  part  in  100), 
the  controls  were  discarded  as  unnecessary. 

BxP:eRIMENTS   ON  FROGS 

Dose  0.1  to  0.2  milligram  per  gram  weight  of  frog. 
After  the  injection  of  the  above  quantities  there  were  ob- 
served the  following  symptoms:  Discomfort  from  adminis- 
tration, slightly  increased  respiration,  and  with  the  larger 
doses  an  odor  of  mercaptan.  These  effects  passed  off 
rapidly  and  were  followed  by  a  complete  recovery. 

Dose  0.25  milligram  per  gram  weight  of  frog. 
This  dose  caused  increased  respiration  and  discomfort. 
The  latter  symptom  was  manifested  in  an  incoordinated 
effort  to  escape  from  the  wire  cage  by  pushing  the  head 
against  the  sides  either  at  the  wires  or  at  the  spaces  be- 
tween them,  as  if  the  animal's  vision  were  imperfect.  After 
these  attempts  the  frogs  squat  with  half-closed  eyes  and 
move  only  when  stimulated.  All  the  reflexes  were  present, 
but,  with  the  exception  of  the  toe  reflex,  all  were  less 
marked  than  usual.  In  one-half  hour  or  less  complete  re- 
covery of  the  frog  was  observed. 

Dose  O.J  J  milligram  per  gram  weight  of  frog. 
With  the  administration  of  this  dose  the  condition  of 
inertia  noticed  with  the  preceding  dose  became  more  pro- 
nounced and  deepened  into  lethargy.  The  frog  lay  on  its 
back  with  all  the  reflexes  suspended,  except  the  toe  reflex. 
Respiration  was  shallow  and  scarcely  visible  and  the  heart 
beat  was  observed  with  some  difficulty.  There  were 
occasional  spasmodic  contractions  of  the  toes;  these  con- 
tractions are  more  frequent  in  the  hind  feet.  In  a  period 
of  something  less  than  one  hour  recovery  set  in. 


45 

Dose  0.5  milligram  per  gram  weight  of  frog. 
Upon  administration  of  this  dose  the  condition  of  lethargy- 
noticed  with  the  smaller  dose  of  0.33  milligram  passed  into 
a  loss  of  animation  with  a  complete  suspension  of  all  re- 
flexes. The  respiration  ceased.  The  heart  beat  could  not 
be  observed.  The  frog  lay  limply  on  the  hand  in  a  comatose 
state.  Nevertheless,  iij  a  period  somewhat  under  two  hours 
there  was  complete  recovery. 

Dose  0.66  milligram  per  gram  weight  of  frog. 
Of  the  two  frogs  which  received  this  amount  of  mer- 
captan,  one  recovered  and  one  died.  In  the  one  which  re- 
covered the  symptoms  were  the  same  as  those  observed 
with  the  administration  of  0.5  milligram  per  gram  weight 
of  frog.     But   these   symptoms   were   more   pronounced. 

Lethal  dose. 
With  a  dosage  of  i  milligram  per  gram  weight  of  frog 
death  occurred  in  ninety  per  cent,  of  the  cases.  This  ap- 
peared to  be  nearly  instantaneous,  but  the  dividing  line 
between  the  suspended  animation  following  the  smaller 
doses  and  this  real  death  was  so  poorly  defined  that  at 
least  four  hours  should  pass  before  autopsy. 

Post-mortem  examination. 
In  all  cases  in  which  death  followed  the  administration 
of  the  toxic  substance,  there  was  noticed  a  faint  exha- 
lation of  mercaptan  and  an  absence  of  rigor  mortis.  Upon 
pithing  the  brain  no  response  was  obtained.  Pithing  the 
spinal  cord  produced  incoordinated  muscular  contractions. 
The  muscles  were  highly  irritable,  but  otherwise  appeared 
normal.  The  abdominal  cavity  usually  contained  serous 
fluid.  All  the  tissues  reeked  of  mercaptan.  The  heart 
was  about  two-thirds  its  normal  size;  the  ventricle  was 
pale  and  firm;  the  auricular  ventricular  proportion  was  un- 
changed; electrical  stimulation  produced  systole;  mechani- 
cal stimulation  was  not  followed  by  a  contraction.  The 
lungs  and  the  intestines  appeared  normal. 


46 

Several  control  experiments  were  made  on  frogs  which 
after  receiving  the  injection  were  placed  in  water  at  32°  C. 
This  was  done  as  it  was  feared  that  the  cold  might  di- 
minish the  power  of  elimination  of  the  frog.  The  period 
of  recovery  was  found  to  be  but  very  slightly  shortened  in 
these  cases. 

Two  frogs  which  had  received  0.33  milligram  per  gram 
weight  of  frog  were  placed  in  dry  jars,  A  and  B.  Jar  A 
was  connected  with  a  suction  pump,  while  jar  B  was  not. 
The  frog  in  jar  A  was  able  to  turn  over  and  recovered  its 
reflexes  twenty  minutes  sooner  than  the  frog  in  jar  B. 

These  jars,  in  another  series  of  experiments,  were  placed 
in  water  at  34°  C,  without,  however,  affecting  the  result 
in  the  least. 

This  experiment  was  again  repeated  with  another  varia- 
tion. The  entering  air  was  passed  through  water  in  order 
to  avoid  the  drying  of  the  frogs'  skins,  and  thus  retarding 
or  preventing  elimination.  The  ultimate  results  were  un- 
affected. 

Elimination. 

Ethyl-mercaptan  is  probably  eliminated  through  the  skin 
as  evidenced  by  the  odor  of  the  exhalations  from  the 
animal. 

Conclusion. 

Mercaptan  has  a  powerful  and  lasting  anaesthetic  effect 
on  frogs.  A  lethal  dose  killed  by  depressing  the  heart. 
It  is  difficult  to  name  the  condition  which  follows  the  ad- 
ministration of  the  drug.  One  observer "^  has  called  it 
catalepsy. 

Experiments  on  guinea  pigs. 

Injections  of  ethyl-mercaptan  in  50  per  cent,  alcohol 
were  made  subcutaneously  into   the  guinea  pigs.^ 

1  Richardson:  Aesclepiad,  L,ondon,  1899,  p.  321. 

2  It  was  found  that  ethyl-mercaptan  was  soluble  in  four  parts  of  olive 
oil. 


47 

Dose  I  milligram  per  lOO  gram  weight  of  pig. 

After  this  dose  was  given  there  was  slight  restlessness  of 

short  duration  probably  caused  more  by  the  handling  than 

from  the  effect  of  the  drug.     There  was  a  very  slight  but 

transient  odor  of  mercaptan  from  the  breath  of  the  animal. 

Dose  2  milligrams  per  lOO  gram  weight  of  pig. 
From    the    administration    of   this    dose    the   results    were 
likewise  very  mild.     One  case,  however,  showed  some  tem- 
perature reduction  and  a  slight  dilatation  of  the  pupils. 

Dose  J  milligrams  per  loo  gram,  weight  of  pig. 
With    this    dosage    the    period    of    restlessness    and    dis- 
comfort became  more  pronounced.     There  was  a  persistent 
pupillary  dilatation  and  a  variable  but  constantly  occurring 
temperature  reduction. 

Dose  4  milligrams  per  lOO  gram  weight  of  pig. 
After  this  dose  there  followed  a  short  period  of  dullness 
and  indifference  to  manipulation,  suggesting  a  slight  general 
anaesthetic  effect.  The  reflexes  were  all  present.  The 
pupillary  dilatation  was  marked.  There  was  a  slight  tem- 
perature fall.  The  respiration  was  stimulated.  The  symp- 
toms gradually  disappeared  and  a  return  to  normal  con- 
dition followed. 

Dose  5  milligrams  per  lOO  gram  weight  of  pig. 
The  weight  of  the  guinea  pig  was  210  grams.  Upon 
administration  of  this  dose  the  animal  showed  immediate 
discomfort — scratching  its  nose,  moving  its  head  from  side 
to  side  and  resisting  handling.  A  strong  odor  of  mercaptan 
was  noticed  from  the  breath.  After  ten  minutes  tremors 
developed,  the  corneal  reflex  disappeared,  the  pupils  were 
dilated  and  failed  to  respond  to  light,  the  temperature  fell 
3°  F.  and  the  respirations  became  very  labored.  After  fifteen 
minutes,  all  the  reflexes  were  lost  and  the  guinea  pig  could 
not  maintain  its  equilibrium.  After  twenty  minutes  the 
guinea  pig  seemed  to  be  dead,  but  the    heart  continued   to 


48 

beat  feebly.  After  thirty  minutes  the  heart  stopped  beat- 
ing and  the  guinea  pig  was  obviously  dead. 

Autopsy:  No  rigor  mortis  was  observed  30  minutes  after 
death.  A  strong  odor  of  mercaptan  was  present  from  all 
the  tissues.  The  peritoneum  was  bluish;  the  veins  engorged; 
the  blood  of  a  dark  brown  color.  The  heart  did  not 
respond  to  stimulation.  All  the  heart  cavities  contained 
blood  clots.  The  thoracic  cavity  contained  brownish  serum. 
Lungs  and  other  organs  were  unchanged. 

Death  appeared  to  be  due  to  asphyxiation  from  the 
rapid  reduction  of  the  hemoglobin  or  to  direct  respiratory 
paralysis. 

In  the  second  experiment,  a  guinea  pig  weighing  304 
grams  was  used.  Soon  after  the  administration  the  animal 
was  very  uncomfortable.  It  squealed  readily  and  scratched 
its  nose.  A  strong  odor  of  mercaptan  was  noticed  from 
the  breath.  After  ten  minutes,  the  respirations  were  in- 
creased, and  the  pupils  were  dilated,  showing  a  slight 
response  to  light.  After  fifteen  minutes  the  temperature 
fell  1.5°  F.  No  tremors  or  loss  of  reflexes  were  observed. 
After  thirty  minutes  the  pig  could  not  sit  upright,  and 
moved  unwillingly.  The  respiration  was  rapid  and  shal- 
low. These  symptoms  gradually  wore  off,  and  at  the 
end  of  two  hours  the  pig  was  returned  to  the  cage,  entirely 
recovered. 

The  third  pig  weighed  492  grams.  After  the  injection 
of  the  dose  there  was  noticed  prompt  discomfort,  but  not  as 
marked  as  in  the  case  of  the  second  pig.  The  respiration 
was  increased  and  the  heart  was  very  rapid  and  feeble. 
A  strong  odor  of  mercaptan  was  smelt  on  the  breath.  After 
fifteen  minutes,  the  pupils  were  dilated  but  responded  to 
light.  Occasional  tremors  were  observed,  and  the  tempera- 
ature  fell  2.5°  F.  After  twenty  minutes  there  was  a  loss 
of  equilibrium  and  the  reflexes. 

These  symptoms  gradually  disappeared,  and  at  the  end 
of  two  hours  the  animal  was  returned  to  the  cage  appar- 
ently   recovered,    but    still    weak    in    the    hind    legs.     This 


49 

weakness  continued  but  the  pig  fed  well  and  seemed  con- 
tented. 

Two  days  later  the  pig  was  found  dead  in  the  cage. 

Autopsy:  Cyanosis  of  the  membranes  and  tongue.  No 
rigidity  or  odor  of  mercaptan  from  the  tissues.  No  evi- 
dence of  injury  was  seen.  In  the  abdominal  cavity  there 
was  a  brownish  serum;  the  vessels  were  engorged,  and  the 
blood  was  dark.  The  Mver  appeared  normal.  The  kidneys 
were  hard,  congested  and  the  capsule  was  adherent.  Upon 
microscopical  examination,  after  staining,  the  typical  lesions 
of  acute  parenchymatous  nephritis  were  observed.  The 
thoracic  cavity  also  contained  a  brownish  serum.  The  lungs 
were  congested  and  edematous.  The  ventricles  of  the 
heart  were  empty,  while  the  auricles  contained  a  brownish 
blood  clot.  Death  was  probably  due  either  to  nephritis, 
or  the  edema  of  the  lungs,  or  the  change  in  the  blood. 

Pig  number  4  weighed  501  grams.  After  administration 
of  the  dose,  discomfort  was  pronounced  and  immediate.  A 
strong  odor  of  mercaptan  was  present  on  the  breath.  After 
five  minutes,  the  respiration  was  shallow  and  difficult ;  the  heart 
was  rapid  and  feeble.  After  ten  minutes  equilibrium  was  lost 
and  all  the  reflexes  disappeared.  Marked  tremors  were 
present  and  the  temperature  was  reduced  3°  F,  After 
fifteen  minutes  the  pig  seemed  to  be  dead,  but  the  heart 
continued  to  beat  feebly.  The  animal  gradually  recovered, 
however,  and  two  hours  later  was  returned  to  the  cage 
apparently  well  but  feeble.  The  following  day  the  pig 
was   found   dead. 

Autopsy:  The  post-mortem  findings  were  identical  with 
those  of  pig  number  3,  except  that  the  odor  of  the  mer- 
captan was  still  present  in  the  tissue.  Death  was  probably 
due  to  the  nephritis  or  the  condition  of  the  blood. 

Pig  number  5  weighed  320  grams.  After  the  administration  of 
the  dose  there  was  observed  immediate  discomfort.  A  strong 
odor  of  mercaptan  was  present  on  the  breath.  After  ten  min- 
utes the  pupils  were  dilated  but  responded  to  light.  The  res- 
pirations were  gasping  and  the  temperature  fell  2°  F.     No 


50 

tremors  were  present.  After  fifteen  minutes  the  pig  lay 
on  its  side  unable  to  move  voluntarily.  All  the  reflexes 
were  absent.  The  heart  was  rapid.  Spasmodic  contrac- 
tions of  the  hind  extremities  were  observed.  After  thirty 
minutes  the  pig  was  able  to  sit  up  with  an  effort,  but  it 
made  no  attempts  to  move  about.  The  contractions  of 
the  hind  legs  continued.  After  forty  minutes,  the  res- 
piration was  very  shallow,  and  the  heart  beat  was  scarcely 
felt.  The  reflexes,  however,  began  to  return.  After  fifty 
minutes,  the  pig  was  able  to  nose  about  feebly  and  resent 
interference.  Animal  gradually  recovered  and  was  returned 
to  the  cage  in  good  condition.  No  after  ill  effects  were 
noticed. 

Pig  number  6  weighed  450  grams.  Immediate  discom- 
fort was  evident  after  the  administration  of  the  dose; 
the  animal  scratched  its  nose  and  squealed  occasion- 
ally. After  ten  minutes,  the  respirations  were  shallow 
and  there  was  a  strong  mercaptan  odor  on  the  breath. 
There  was  slight  anaesthesia  of  the  cornea;  the  pupils 
were  dilated  but  responded  to  light.  The  temperature 
fell  2.2°  F.  After  fifteen  minutes  the  animal  lay  on 
its  side.  The  hind  legs  were  paralyzed.  There  were 
tremors  and  involuntary  evacuation  of  feces.  After  thirty 
minutes  the  animal  could  rise  on  its  forelegs,  but  dragged 
its  hind  legs.  The  anaesthesia  of  the  cornea  was  less 
marked.  The  breathing  was  forced,  slow  and  shallow. 
This  pig  at  no  time  showed  complete  loss  of  reflexes.  All 
the  symptoms  gradually  wore  off  and  the  animal  was  re- 
turned to  the  cage  apparently  recovered.  Five  days  later, 
however,  the  pig  was  found  dead. 

Autopsy:  There  was  no  rigidity,  no  odor  of  mercaptan 
and  no  evidence  of  injury.  The  mucous  membranes  and 
tongue  were  cyanotic.  In  the  abdominal  cavity,  the  peri- 
toneum was  engorged,  and  it  contained  a  brownish  serum. 
The  blood  was  very  dark  and  venous.  The  liver  was 
flabby  and  the  gall  bladder  was  full  of  bile.  The  stomach 
was  distended  with  gas.     The  kidneys  were  large,   swollen 


51 

and  hard.  The  renal  capsule  was  adherent.  In  general, 
on  microscopical  examination  the  typical  lesions  of  acute 
parenchymatous  nephritis  were  observed.  In  the  thoracic 
cavity  there  was  present  a  bloody  serous  exudate;  the  lungs 
were  congested.  Heart  cavities  were  full  of  brownish, 
clotted  blood.  Death  was  due  either  to  the  nephritis  or 
the  blood  condition. 

Comparison   of  the  toxic   effects  of  methyl-,  ethyl-, 
propyl-,  and  butyl-mercaptan  on  guinea  pigs. 

In  order  to  compare  the  pharmacological  effects  of  the 
four  lower  mercaptans,  a  guinea  pig  was  placed  in  each  of 
four  two-liter  jars,  the  drug  was  introduced  on  cotton, 
and  the  jar  carefully  sealed. 

In  jar  number  i  was  placed  a  guinea  pig  weighing  295 
grams.  Approximately  8.0  cc.  of  methyl-mercaptan  were 
placed  on  a  piece  of  cotton  and  introduced  into  the  jar. 
Within  a  few  seconds  the  animal  rubbed  its  nose,  but 
showed  no  other  sign  of  excitement.  In  twenty  seconds 
the  animal  fell  over  and  seemed  completely  anaesthetized. 
The  respirations  were  gasping  in  type.  One  minute  after 
introduction,  the  pig  was  removed  from  the  jar.  No  heart 
beat  and  no  respiratory  movements  were  noticed.  Re- 
laxation  was  complete. 

Autopsy:  The  tongue  was  bluish;  a  slight  odor  of  mer- 
captan  was  present.  The  muscles  appeared  bluish  and  cy- 
anotic. The  heart  was  in  diastole,  and  did  not  respond  to 
stimulation.  The  blood  was  dark  and  venous.  The  lungs 
were  congested.  The  kidneys  and  liver  appeared  normal. 
It  was  believed  that  death  was  due  to  respiratory  paralysis. 

In  jar  number  2  a  guinea  pig  was  placed  weighing  380 
grams.  10  cc.  of  ethyl-mercaptan  were  introduced  on  a 
piece  of  cotton.  Immediately  after  introduction  the  animal 
showed  signs  of  irritation,  such  as  scratching  its  muzzle, 
climbing  up  the  sides  of  the  jar,  etc.  After  thirty  seconds 
the  animal  was  completely  relaxed,  and  lay  on  its  side. 
After   one   minute,    the   breathing   was   slow,    irregular   and 


52 

gasping.  In  i  minute  and  20  seconds  the  pig  was  removed. 
The  relaxation  was  complete;  complete  anaesthesia  of  the 
cornea.  The  heart  could  be  felt;  slight  tremors  of  the 
fore  legs  were  present.  The  respiration,  which  had  ceased, 
gradually  returned,  becoming  rapid  and  shallow.  Two 
minutes  after  removal  the  pig  tried  to  sit  up.  In  about 
three  minutes  after  removal  it  appeared  normal.  After 
four  minutes  it  nibbled  at  some  paper  and  resisted  manipu- 
lation.    Recovery  was  rapid  and  complete. 

In  jar  number  3  a  pig  weighing  260  grams  was  placed 
together  with  10  cc.  of  propyl  mercaptan.  The  animal 
became  at  once  very  irritable,  as  evinced  by  the  scratching 
of  the  nose  and  climbing  up  the  side  of  the  jar.  After  10 
seconds  the  respirations  became  increased.  In  15  seconds 
the  respirations  were  shallow  and  gasping.  After  one 
minute  it  lay  on  its  side,  completely  relaxed,  gasping,  with 
eyes  closed.  The  animal  was  removed  from  the  jar  in 
one  minute  and  twenty  seconds.  The  relaxation  was  com- 
plete; there  was  no  heart  beat.  After  15  minutes,  as  the 
pig  showed  no  signs  of  recovery,  a  post-mortem  examination 
was  made.  The  membranes  and  the  tongue  were  cyanosed. 
Odor  of  mercaptan  present.  The  muscles  were  bluish. 
The  heart  was  still  beating,  rapid  and  very  feeble.  It  was 
thought  at  that  time  that  the  pig  might  have  recovered  if 
it  had  been  let  alone.  In  45  minutes  the  heart  stopped  in 
diastole.  The  lungs  were  congested.  The  liver  and  the 
kidneys  were  normal.     The  veins  were  engorged. 

In  jar  number  4  a  guinea  pig  weighing  480  grams  was 
placed  together  with  10  cc.  of  iso-butyl-mercaptan.  Im- 
mediately after  introduction  the  animal  showed  signs  of 
discomfort  and  irritation.  In  30  seconds  the  respirations 
were  gasping  and  the  eyes  were  closed.  The  animal  fell 
over  in  i  minute.  In  i  minute  and  20  seconds  there  were 
no  signs  of  respiration.  The  animal  was  removed  from  the 
jar  in  2  minutes.  There  was  complete  anaesthesia  of  cor- 
nea, and  complete  relaxation.  In  two  and  a  half  minutes 
after   removal   slight   twitchings  of  the   hind   feet  were   ob- 


53 

served;  the  heart  could  be  felt  with  difficulty.  After  3 
minutes  the  respiration  returned,  shallow  and  gasping.  The 
corneal  reflex  was  present,  but  feeble ;  the  pupils  were  widely- 
dilated  but  reacted  feebly  to  light.  The  animal  gradually 
recovered.^ 

The  general  conclusions  that  may  be  drawn  from  these 
experiments  are:  The  inhalation  of  the  four  lower  mer- 
captans  produce  identfcal  results,  and  it  is  safe  to  assume 
that  the  effects  produced  by  their  administration  in  any 
other  way  would  be  the  same.  The  effects  are:  first,  dis- 
comfort, then  very  rapid  and  complete  anaesthesia.  Death 
is  caused  by  respiratory  paralysis.  If  the  pig  is  very 
promptly  removed  very  rapid  recovery  ensues. 

Elimination:  Up  to  a  certain  point  the  drug  would  seem 
to    be    eliminated    by    the    breath.     Over    and    above    this 
amount  which   might  be  considered   as  the  point  of  tissue 
saturation,    excretion    is    aided    by    the    kidneys.     Proof    of 
this  is  shown  by  the  experiments  on  the  dog.     (See  below.) 
Effects  of  mercaptan  on  a  dog. 
Great  difficulty  was  experienced  in  obtaining  a  dog  that 
would  tolerate  even  the  odor  of  the  drug.     Finally,   after 
five  attempts,  a  ten-kilo  dog  of  the  pointer  type  was  pro- 
cured.    The   drug   was   administered   once  a  week  in  a  cap- 
sule with  the  food  after  a  twenty -four  hour  fast. 
Dose   oj   less    than   o.i    gram. 
A  dosage  of  less  than  o.i   gram  caused  very  slight  dis- 
comfort and  a  transient  odor  of  mercaptan  on  the  breath. 
No  increased  peristalsis  was  observed.     The  drug  could  not 
be  recovered  from  the  urine  or  the  feces. 
Dose    of    O.I    gram. 
This   dosage   caused   slight  discomfort,   slightly   increased 
'  A  control  experiment  was  made.     A  guinea  pig  was  placed  in  a 
sealed  jar  containing  no  drug.     The  animal  showed  no  signs  of  discomfort. 
The  animal  was  kept  in  the  jar  for  three  hours,  and  there  was  no  sign  of 
asphyxia,  and  the  pig  was  removed  in  good  condition.     The  animal  did 
not  defecate  or  urinate  while  in  the  jar. 


54 

the  peristalsis  and  caused  a  strong  but  fleeting  odor  of  mer- 
captan  on  the  breath;     0.0038  gram  was  recovered  from  the 
urine.     None  was  present  in  the  feces. 
Dose  of  0.1  j  gram. 

After  this  dose  was  given  a  strong  odor  of  mercaptan 
appeared  on  the  breath.  SUght  discomfort  was  present; 
the  peristalsis  was  increased.  An  average  of  0.0048  gram 
was  recovered  in  the  urine,  none  in  the  feces.  There  was 
a  slight  polyiuria,  and  a  marked  trace  of  albumin.^  The 
albumin  entirely  disappeared  in  48  hours,  nor  could  the 
drug  be  recovered  from  the  urine  after  that  time. 
Dose  of  0.2  gram. 

This  dosage  marked  the  limit  of  toleration  and  was  only 
given  once  without  causing  vomiting.  The  administration 
was  followed  by  slight  discomfort,  increased  peristalsis,  a 
strong  odor  of  mercaptan  on  the  breath,  and  usually  by 
vomiting.  The  urine  was  diminished  in  quantity,  highly 
colored,  and  of  increased  specific  gravity.  It  contained 
leucocytes  and  red  blood  cells,  but  no  casts  or  shreds.  A 
large  amount  of  albumin  was  present.  It  is  very  interesting 
to  note  that  a  very  definite  trace  of  glucose  was  detected 
in  this  lurine;  0.0068  gram  of  the  drug  was  recovered  from 
the  urine,  but  none  from  the  feces. 

Effect  of  mercaptan  on  man. 

As  the  result  of  the  exposure  to  and  the  inhalation  of 
mercaptan  by  human  beings  several  symptoms  were  ob- 
served that  are  highly  significant.  There  was  a  prompt 
irritation  of  the  conjunctivae  with  lacrymation  and  photo- 
phobia. The  nasal  mucous  membrane  was  also  irritated, 
and  a  profuse  discharge  from  the  nose  resulted.  Either 
due  to  the  extremely  unpleasant  odor  or  to  the  fact  that 
some  mercaptan  was  swallowed  with  the  saliva,  nausea 
may  result.  In  susceptible  individuals  this  nausea  is  quite 
severe,  and  may  be  followed  by  retching  and  vomiting. 
1  This  albumin  was  distinctly  pathological,  and  should  not  be  con- 
fused with  the  slight  traces  of  albumin  usually  present  in  the  urine  of  a  dog. 


55 

In  one  case,  the  subject  was  so  susceptible  that  as  soon  as 
he  worked  with  the  mercaptan  for  half  an  hour,  he  began 
to  feel  nauseated;  he  did  not  vomit,  but  severe  abdominal 
cramps  made  him  feel  very  faint;  he  had  a  severe  attack 
of  diarrhoea.  He  felt  very  much  relieved  as  soon  as  he 
left   the   room.     This   happened    three    days   in    succession. 

The  feeling  of  mental  prostration  and  lassitude  is  actual 
and  not  imaginary,  and  there  is  a  strong  desire  to  sleep  as 
evidenced  by  constant  yawning. 

Effect  of  mercaptan  on  seedlings. 

Five  medium  petri  dishes  were  sown  with  timothy  seeds, 
using  white  blotting  paper  as  the  ground.  The  dishes  were 
kept  at  room  temperature. 

To  dish  number  i  was  added  i  drop  of  i  per  cent, 
aqueous  ethyl-mercaptan,  with  the  result  that  total  death 
followed  at  the  point  of  application.  The  same  results 
were  obtained  with  two  and  with  five  drops.  The  tops  of 
the  sprouts  turned  brown,  but,  except  at  the  point  of  appli- 
cation, recovered.  These  plates  were  kept  uncovered  all 
the  time,   permitting  rapid  evaporation. 

The  other  plates  were  kept  covered  permitting  no  free 
entrance  and  exit  of  air  and  moisture.  In  this  case  the 
addition  of  a  few  drops  of  i  per  cent,  aqueous  ethyl-mer- 
captan caused  browning  and  general  death. 

Effect  of  mercaptan  on  blood  pigments. 

It  was  thought  advisable  to  investigate  the  action  of  the 
thio-alcbhols  on  blood  and  blood  pigments.  Very  inter- 
esting and  instructive  results  were  obtained. 

Blood  was  obtained  from  a  dog  by  a  canula  in  the 
femoral  artery.  The  blood  was  defibrinated  by  vigorous 
stirring.  The  experiments  were  performed  on  this  de- 
fibrinated  blood. 

The  blood  was  diluted  about  30  times  with  distilled 
water.  To  this  blood  there  were  added  3  drops  of  propyl- 
mercaptan.  The  blood  became  immediately  brownish  in 
color.     Later   on    (five   minutes)    disintegrative   changes   set 


56 

in.  There  was  a  complete  hemolysis  of  the  red  blood  cells, 
the  albumin  became  coagulated,-  and,  after  a  few  minutes, 
settled  to  the  bottom  of  the  test  tube.  The  supernatant 
fluid  was  clear,  brownish  red,  and  upon  examination  with 
■the  spectroscope  gave  a  spectrum  similar  to  that  of  hema- 
tin.  With  lesser  concentrations  of  propyl-mercaptan  the 
hemolysis  was  less  and  there  was  no  precipitation  of  the 
proteins  of  the  blood. 

Special  attention  was  paid  to  the  spectrum  obtained 
when  hemoglobin  solutions  were  treated  with  mercaptan.'^ 
The  defibrinated  blood  was  diluted  with  forty  parts  of  dis- 
tilled water.  To  this  there  was  added  a  very  dilute  solu- 
tion of  mercaptan.  The  pigment  was  then  examined  with 
the  spectroscope,  using  oxyhemoglobin  as  a  control.  A 
broad,  dark  band  was  noticed  between  D  and  E,  and 
a  narrower,  lighter  band  was  present  just  to  the  left  of 
D.  This  somewhat  resembles  the  bands  obtained  with 
methemoglobin,  but  they  are  not  identical.  At  first 
it  was  thought  that,  perhaps,  the  mercaptan  hemo- 
globin band  was  similar  to  the  hydrogen  sulfide-hemo- 
globin  spectrum.  A  specimen  of  sulf-hemoglobin  was, 
therefore,  prepared  by  passing  hydrogen  sulfide  into  a 
solution  of  blood,  and  the  spectrum  obtained  was  then  com- 
pared with  the  mercaptan  spectrum.  It  was  found  that  it 
was    distinctly    different   from    the    mercaptan    hemoglobin. 

General  concivUSions. 
Mercaptan  when  given  subcutaneously  to  either  cold-  or 
warm-blooded  animals  has  a  marked  anaesthetic  effect. 
The  first  result  of  the  administration  is  irritation,  and  then 
follow  promptly  abolished  reflexes  and  loss  of  consciousness. 
Respiration  is  at  first  increased  and  then  slowed.  The 
heart  is  rapid  and  feeble,  and,  in  warm-blooded  animals, 
the  temperature  is  much  reduced,  and  the  color  of  the  blood 
is  changed  to  a  dark  brown.  If  the  elimination  by  means 
of  the  breath  is  not  prompt  and  thorough,  the  kidneys  be- 

1  In  all  these  experiments  propyl-mercaptan  was  used. 


57 

come  impaired,  and  acute  parenchymatous  nephritis  super- 
venes. This  condition  causes  death  after  an  interval  of 
from  one  to  five  days.  When  death  follows  promptly  after 
the  administration  it  is  probably  due  to  respiratory  de- 
pression. 

The  inhalation  of  mercaptan  causes  rapid  and  over- 
whelming results.  Anaesthesia  is  complete  in  less  than  a 
minute,  and  if  the  animal  is  not  promptly  exposed  to  the 
air,    death   follows   quickly   from   respiratory   paralysis. 

The  administration  of  the  drug  per  os  causes  nausea, 
vomiting  and  increased  peristalsis.  There  is  irritation  and 
impairment  of  the  kidneys,  and  these  organs  are  rendered 
more  permeable  to  the  passage  of  glucose.  This  damage, 
as  shown  by  the  urinary  findings,  rapidly  passes  off  and  the 
kidneys  return  to  normal. 

Mercaptan  is  an  irritant  poison  to  living  tissue.  Ex- 
posm"e,  however  limited,  will  cause  a  pronounced  and 
chronic  conjunctivitis  and  an  inflammation  of  the  nasal 
mucous  membrane  in  human  beings.  To  plant  life  it  is 
also  injurious  causing  local  death  at  the  point  of  contact, 
and,  if  evaporation  is  diminished,   general  destruction. 


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59 

20.  Ladenburg,  "Mercaptan,"  Liebig's  Annalen,  cxlv,  p.  189. 

21.  Liebig,  J.,  "Mercaptan,"  Ibid.,  xi,  p.  14. 

22.  Nasini,  "Mercaptan,"  Ber.  d.  deut.  chem.  Ces.,  xv,  p.  2882. 

23.  Nencki,  M.,  "Zur  Kenntniss  der  faulniss  Prozesse,"  Chem.  Ber.,  1877, 

X,  p.  1032. 

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f.  Chem.,  1889,  X,  p.  506. 

"Ueber  das  Vorkommen  von  methyl  mercaptan  im  menschlichen 

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xxviii,  p.  206. 

24.  Nencki,  M.,  and  Sieber,  M.,  "Zur  kenntniss  der  beider  Eiweissgahrung 

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"Ueber  eine  neue  Methode  die  physiologische  oxidation  zu  Messen, 

und  ueber  den  Einflus  der  Gifte  und   Krankheiten  auf  die  selbe," 

Pfliiger's  Arch.,  xxxi,  p.  314. 

"Methyl  mercaptan  als  Bestandtheil  der  menschlichen  Darmgase," 

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25.  Neuberg,  C,  and  Grosser,  "Eine  neue  schwefelhaltiges  Substanz  aus 

dem  Hundeham,"  Centralbl.  Physiol.,  1906,  xix,  p.  316. 

26.  Neumann,  "Mercaptan,"  Arch.  J.  Hyg.,  1893,  xix,  p.  126. 

27.  Niemann,  F.,  "Ueber  die  Menge  fluchtige  schwefe!  Verbindungen  in 

den  festen  Ausscheidungen,"  Ibid.,  1893,  xix,  p.  117. 

28.  Obermayer,  "Mercaptan,"  Ber.  d.  deut.  chem.  Ges.,  xx,  p.  2918. 

29.  Pagliani,  "Ethyl  Mercaptan,"  Ibid.,  xi,  p.  155. 

30.  Pigorini,   L.,   "Fate  of  Glucose    Mercaptans  in  the  Animal  Body," 

Arch.  Pharmacol.,  1911,  xi,  p.   i. 

31.  Prinz,  "Mercaptan,"  Liebig's  Annalen,  ccxxiii,  p.  377. 

32.  Rathke,  "Mercaptan,"  Ibid.,  clxi,  p.  148. 

33.  Regnault,  "Ethyl  Mercaptan,"  Ibid.,  xxxiv,  p.  25. 

34.  Rekowski,  "Toxicity  of  Mercaptan,"  Ann.  de  I'Inst.  Imp.  de  St.  Peiers- 

bourg,  1893,  p.  205. 

35.  Reymann,  "Butan-2-thiol,"  Ber.  d.  deut.  chem.  Ges.,  vii,  p.  1287. 

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Aesclepiad,  London,  1889,  vi,  p.  321. 

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38.  Rubner,  M.,  "Ueber  das  Vorkommen  der  Merkaptane,"  Ilyg-  Rund- 

schau, 1893,  iii,  p.  525. 

"Ueber   die   Vorkommen   von    Merkaptan,"   Arch.  f.   Ilyg.,    1893, 

xix,  p.  136. 

39.  Rubner,  Niemann,  and  Balistreri,  "Ueber  das  Vorkommen  von  Mer- 

captan," Ibid.,  1893,  xix,  p.  136. 


6o 

40.  Salkowski,  E.  and  H.,  "Zur  Kennttiiss  der  EiweissfauUniss,"  Zeit.  f. 

physiol.  Chemie,  1884,  viii,  p.  47. 

"Weitrer  Beitrage,"  etc.,  Ber.  d.  deut.  chem.  Ges.,  xii,  pp.  107,  648, 

1438,  1879;  xiii,  pp.  1880,  1896,  2217. 

41.  Saytzew    and    Grabowski,    "Butyl    Mercaptan,"    Liebig's    Annalen, 

clxxi,  p.  251. 

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beim  schmelzen  des  Eiweisses  mit  Aetzkali,"  Maly's  Jahresb.  d. 
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44.  Scnitzenberger,  "Die  Gahrungserscheinungen,"  1876,  p.  144. 

45.  Schreiner,  P.,  "Ueber  die  chemische  Bestandtheile  Melonitha  vulgaris, 

Liebig's  Annalen,  1872,  clxi,  p.  252. 

46.  Weidel   and   Ciamician,    "Ueber   trocken   Distillation,"    Monatsch.  f. 

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1895,  XX,  p.  407. 

48.  Werner,  "Mercaptan,"  Ber.  d.  deut.  chem.  Ges.,  xxv,  p.  64. 

49.  Zeise,  "Ethyl  Mercaptan,"  Liebig's  Annalen,  xi,  p.  i. 

50.  Zuntz,  N.,  "Eine  methode  zur  Aufsammlung  und  analyse  von  Darm 

und  Gahrungs  Gasen,"  Arch.  f.  Physiol.,  1899,  p.  579. 


BIOGRAPHICAL. 

Frederic  Grosvenor  Goodridge  was  born  in  New  York 
City  on  September  25,  1874.  He  studied  at  St.  Paul's 
School,  Concord,  New  Hampshire,  and  abroad.  He  gradu- 
ated from  Harvard  University  with  the  degree  of  Bachelor 
of  Arts  in  1897  and  from  the  College  of  Physicians  and 
Surgeons  of  Columbia  University  with  the  degree  of  Doctor 
of  Medicine  in  1901. 

In  September,  19 12,  he  matriculated  as  a  candidate  for 
the  degree  of  Doctor  of  Philosophy  in  the  Faculty  of  Pure 
Science,  Columbia  University.  In  19 12  he  was  appointed 
Assistant  in  Biological  Chemistry  in  the  College  of  Physicians 
and  Surgeons;  in  19 13  he  was  promoted  to  the  grade  of 
Instructor. 


PUBLICATIONS. 

1.  Comparative  Dialysis  Experiments.     (With  W.  J.  Gies.)     Proc.  Soc^ 

Exp.  Biol,  and  Med.,  191 1,  viii,  p.  74. 

2.  Notes  on  Fischer's  Theory  on  the  Influence  of  Acids  in  the  Productiort 

of  Edema.     (With  W.  J.  Gies.)     Ibid.,  p.  106. 

3.  The  Relation  of  Uricolysis  to  Suboxidation.     (With  N.  B.  Foster.)) 

Arch.  Internal  Medicine,  1912,  x,  p.  585. 

4.  Non-protein,  Colloidal  Nitrogenous  Substance  in  Cow's  Milk.     (With 

Max  Kahn.)     Biochemical  Bulletin,  1913,  ii,  p.  178. 

5.  The  Urinary  "Sulphtu-"  and  "Nitrogen"  Tests  for  the  Early  Diagnosis-. 

of  Carcinoma.     (With  Max  Kahn.)     Biochemical  Bulletin,  1915,  iv^ 
(In  press.) 


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